Apparatus and method for generating a magnetic field - Patents.com

Abstract

A magnetic field for application to body tissue is generated via an inductor. A connection circuit is provided between the capacitor and the inductor, the connection circuit including at least a first and a second branch. A charging circuit is also provided for electrically charging the capacitor. A switch forming part of the first branch electrically connects the capacitor to the inductor and allows current to flow through the first branch and the inductor, thereby causing the inductor to generate a magnetic field. The current flowing through the first branch represents a first direction of flow with respect to the capacitor. An electrical component forming part of the second branch electrically connects the capacitor to the inductor and allows current to flow between the capacitor and the inductor via the second branch. The current flowing through the second branch represents a second direction of flow with respect to the capacitor. The embodiments provide one or more of: a) an additional inductor in the first or second branch joining the (first) inductor to generate a magnetic field for application to body tissue; b) an additional inductor in series with the (first) inductor, having a variable inductance or provided with a bypass circuit for selectively bypassing or shorting the additional inductor; c) the capacitor having a variable capacitance; d) a switching device in the first branch being capable of being switched between a conducting and a non-conducting state at freely selectable times; e) the first branch leading to the first inductor and the second branch leading to the second inductor; f) a charging circuit being capable of selectively charging the capacitor with a first polarity or a second polarity opposite to the first polarity; g) a DC power supply and an H-bridge replacing the capacitor.

Description

[Technical field]

[0001] The present invention relates to devices and methods for generating a magnetic field, especially for application to (human or animal) body tissue.

[0002] The present invention may be used in particular to generate alternating magnetic fields, i.e. magnetic fields whose magnetic field strength changes over time, and in particular whose magnetic field strength reverses direction over time. Such alternating magnetic fields may be used to generate voltages in body tissues, in particular to induce neural or cellular physiological responses in body tissues, in particular to induce muscular responses in body tissues. In some cases, the voltage may be sufficient to induce a therapeutic effect or some other (desired) effect in body tissues, i.e. not necessarily a therapeutic effect, for example, strengthening of muscle tissue. [Background technology]

[0003] Various devices for generating an alternating magnetic field for application to body tissue are known in the art. FIG. 1 shows, in schematic form, a circuit diagram of a device for generating an alternating magnetic field known to the inventor (but not admitted to be prior art). The circuit shown in FIG. 1 includes a capacitor 101 electrically connected to an inductor 102 via two branches 105 and 106 of a connecting circuit. The capacitor 101 is also connected to a source of electrical energy, such as a voltage source 107, via a switch 108. One terminal of each of the capacitor 101, the inductor 102, and the voltage source 107 is connected to ground (represented by a triangle toward the bottom of FIG. 1). Although the switch 108 is shown as a separate circuit element in FIG. 1, it may alternatively be integrated into or form part of the voltage source 107.

[0004] A thyristor 103 forms part of the first branch 105, i.e. one terminal of the thyristor 103 (the left terminal, i.e. the anode, in FIG. 1) is electrically connected to the capacitor 101. A second terminal of the thyristor 103 (the right terminal, i.e. the cathode, in FIG. 1) is electrically connected to the inductor 102. A third terminal, i.e. the gate terminal of the thyristor, is electrically connected to a suitable circuit for "firing" the thyristor 103. The circuit for firing the thyristor 103 is not shown in FIG. 1 but is known to those skilled in the art.

[0005] Similarly, diode 104 forms part of second branch 106, i.e., one terminal of diode 104 (the left terminal, i.e., the cathode in FIG. 1) is electrically connected to capacitor 101. A second terminal of diode 104 (the right terminal, i.e., the anode in FIG. 1) is electrically connected to inductor 102.

[0006] Thus, current may flow between the capacitor 101 and the inductor 102 through either the first branch 105 or the second branch 106 depending on whether the thyristor 103 or the diode 104 is in a conducting or "on" state. In particular, the polarity of the thyristor 103 and the diode 104 is such that only one of these components is in a conducting state at any one time. It will be understood that even when the thyristor 103 or the diode 104 is in a non-conducting state, a small amount of current may still flow through these components. For purposes of this application, "conducting" and "non-conducting" and similar terms are preferably interpreted accordingly.

[0007] The conventional direction of current flow in an electric circuit is defined as the direction in which positive charges flow. Thus, negatively charged carriers, such as electrons, flow in the opposite direction to the conventional flow of current in an electric circuit. According to this convention, the current flowing from the capacitor 101 to the inductor 102 flows (only) through the first branch 105 (assuming the thyristor 103 is in a conducting state), while the current flowing from the inductor 102 to the capacitor 101 flows (only) through the second branch 106 (assuming the diode 104 is in a conducting state).

[0008] The inductor 102 may be brought close to body tissue such that the magnetic field generated by the inductor 102 is applied to the body tissue.

[0009] Typically, the operation of the device shown in Fig. 1 is as follows: Capacitor 101 is charged by voltage source 107. For this, switch 108 is closed at an appropriate time to electrically connect voltage source 107 to capacitor 101. Switch 108 can be operated by an appropriate circuit, again not shown in Fig. 1 but well known to those skilled in the art. After capacitor 101 has been charged for a certain time or to a certain voltage, switch 108 is opened. In the example shown in Fig. 1, capacitor 101 is charged such that (in Fig. 1) the upper terminal is positive and the lower terminal is negative. This is also indicated by the symbols "+" and "-" next to voltage source 107.

[0010] Initially, the charge stored on capacitor 101 remains on capacitor 101 because diode 104 is non-conducting, and current does not (initially) flow from capacitor 101 through first branch 105 to inductor 102 until thyristor 103 fires through its gate terminal.

[0011] The thyristor 103 is then fired via the gate terminal. Current may then flow from the capacitor 101 to the inductor 102, allowing the inductor 102 to generate a magnetic field. As is known in the art, the thyristor 103 remains conductive even when the signal that fired it (the gate current) is no longer present at the gate terminal.

[0012] As current flows from capacitor 101 through first branch 105 and through inductor 102, the charge stored on capacitor 101 (and therefore the voltage across capacitor 101) decreases. This voltage decrease approximately follows a cosine waveform, starting from an initial maximum value when thyristor 103 fires.

[0013] Due to energy losses in the circuit of FIG. 1, the voltage across the two terminals of the capacitor 101 does not follow an exact cosine wave shape over time. Instead, the voltage approaches a cosine wave shape with decay in amplitude, but even this may only be an approximation. The same applies to other voltages, currents, or other variables described herein as (approximately) following a sine or cosine wave shape. This applies to the circuit of FIG. 1 as well as to embodiments of the present invention. Thus, as used herein, "cosine wave shaped," "sine wave shaped," and similar terms are understood to include (approximations of) a cosine wave shape or a sine wave shape with decay in amplitude.

[0014] While the voltage between the two terminals of capacitor 101 decreases, the current through inductor 102 starts from a value of zero and increases to a maximum value, approximately following a sinusoidal waveform. The current through inductor 102 reaches its maximum value at substantially the same time that the charge stored in capacitor 101 drops to zero. The period from the initial firing of thyristor 103 to the current through inductor 102 reaching its maximum value can be considered as 1 / 4 wave, or π / 2.

[0015] At time π / 2, the magnetic field generated by the current through the inductor 102 also reaches a maximum value, and the electrical energy stored in the capacitor 101 becomes zero. In other words, the electrical energy initially stored in the capacitor 101 is then converted into magnetic energy, i.e. the magnetic field generated by the current through the inductor 102. The energy is now stored in a magnetic field. Since the magnetic field resists its reduction, the current continues to flow through the inductor 102 and through the first branch 105. The diode 104 is still non-conducting. This continued current flow therefore charges the capacitor 101, but now with the opposite polarity compared to the initial state. When the capacitor 101 is charged to a negative maximum value (approximately corresponding to the initial maximum charge, but with the opposite polarity), the current through the inductor 102 decreases, and with it the magnetic field, until it becomes zero after half a wave from the initial firing of the thyristor 103, i.e. at time π. At this point, the charge (or voltage) of the capacitor 101 has reached a maximum value of the opposite polarity. Between π / 2 and π, the voltage across capacitor 101 and the current through inductor 102 continue to follow the approximated cosine and sine wave shapes, respectively.

[0016] Approximately at the end of this first half-wave, the thyristor 103 becomes non-conductive and the diode 104 becomes conductive in the forward direction. In the example of FIG. 1, this forward direction corresponds to the current direction from the inductor 102 to the capacitor 101. The process described above for the first half-wave is then effectively repeated during the second half-wave, except that at the time point π (i.e., at the end of the first half-wave or the beginning of the second half-wave), the polarity of the voltage on the capacitor 101 is the opposite polarity of the initial polarity, and similarly, the current direction through the inductor 102 during the second half-wave is opposite to the current direction through the inductor 102 during the first half-wave. Furthermore, the current between the inductor 102 and the capacitor 101 flows through the second branch 106 rather than the first branch 105. The voltage on the capacitor 101 and the current through the inductor 102 continue to follow the (approximated) cosine and sine wave shapes, respectively, that began during the first half-wave.

[0017] Eventually, after the second half-wave, i.e. at time 2π, the system represented by the circuit shown in Figure 1 has returned to its initial state, i.e. capacitor 101 has been charged to its maximum value and is at its initial polarity, and the current through inductor 102 has returned to zero. Diode 104 is now non-conducting. A complete cycle has been performed (two half-waves). The process can then be repeated. Summary of the Invention [Problem to be solved by the invention]

[0018] It is an object of the present invention to provide an apparatus and method that offers greater flexibility than the circuit described above with respect to FIG. [Means for solving the problem]

[0019] The invention therefore provides an apparatus and a method according to the independent claims. Further embodiments are set out in the dependent claims.

[0020] In a first aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a first inductor for generating a magnetic field for application to body tissue; a connection circuit between the power storage device and the first inductor, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device configured to electrically connect the power storage device to the first inductor and to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor, thereby causing the first inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the first inductor; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct electrical current primarily in a forward direction, said electrical component or electrical assembly forming part of a second branch such that current can flow between the power storage device and the first inductor through the second branch, a forward current flow representing a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; and a second inductor, the second inductor forming part of either the first branch or the second branch.

[0021] Thus, for example, if a second inductor forms part of the second branch, current flowing in the second current direction will also flow through the second inductor (unless the second inductor is bypassed or short-circuited, as will be explained below).

[0022] In some embodiments, a device according to the first aspect can be fabricated similarly to the circuit described with respect to Figure 1. However, the addition of a second inductor to the first branch or the second branch results in significant differences in the structure of the device as well as the operation of the device, as described below.

[0023] When the storage device, especially the capacitor, is used as the storage device, it can be substantially regarded as a resonant circuit (or LC circuit) together with the first inductor and the connection circuit. However, in a typical resonant circuit, the current usually takes the same path through the resonant circuit, and does not relate to the direction of the current flow at any time, but in the embodiment according to the first aspect, the current flows through either the first branch or the second branch depending on the current flow direction between the storage device and the first inductor. Furthermore, after one complete cycle (two half waves), assuming that the switching device becomes non-conductive after the first half wave, the current flow stops until the switching device is operated again (e.g., ignited) to allow the current to flow through the first branch. Nevertheless, this behavior can be regarded as somewhat similar to that of a resonant circuit.

[0024] Assuming ideal components, the resonant frequency ω0 (hereafter simply "frequency") of the resonant circuit is determined by the values ​​of the inductance L and capacitance C of the circuit according to ω0=1 / (√(LC)). In real (non-ideal) circuits, other factors known to those skilled in the art will lead to slightly different results, but the above formula can still be used as an approximation, including for the purposes of the present embodiment. Assuming again that a capacitor is used as the storage device in the apparatus according to the first aspect, the capacitance C of the circuit is the same whether the current flows through the first branch or the second branch. However, due to the additional second inductor in either the first branch or the second branch, the applicable inductance of the circuit depends on whether the current flows through the first branch or the second branch. If this is applied to a typical resonant circuit, this would mean that the frequency ω0 of the resonant circuit would depend on whether the current flows through the first branch or the second branch. In other words, the duration of each of the two half-waves of a complete cycle would be different. In an embodiment of the first aspect, the duration of each of the two half waves will be different due to the addition of a second conductor in either the first branch or the second branch.

[0025] For simplicity, the system comprising the storage device, the first inductor, and the first and / or second branches of the connecting circuit (one of which includes the second inductor) will be referred to as a resonant circuit, although strictly speaking it does not necessarily constitute a resonant circuit. Similarly, references to the frequency of a resonant circuit are intended to be understood as references not only to the actual oscillations (especially several successively occurring oscillations), but also to the duration of a half wave, or more generally, to the rate of change (over time) of the current in the resonant circuit, the rate of change (over time) of the voltage at one of its components, or the rate of change (over time) of another electrical property of the resonant circuit.

[0026] Inductors suitable for use as the first inductor and / or the second inductor are known in the art. They may include at least one set of turns (of wire) of any suitable shape, such as generally circular, hexagonal, or rectangular turns, among others. These turns may or may not be wound on a core.

[0027] The switching device of the apparatus according to the first aspect may include a thyristor. The use of a thyristor may be preferred over other switching devices because, once fired, the thyristor remains in a conducting state even after the gate signal is removed. Furthermore, the thyristor switches to a non-conducting state when the polarity of the thyristor's terminals (anode and cathode) is reversed.

[0028] However, instead of a ("normal") thyristor, other types of switching devices may be used, for example a gate turn-off (GTO) thyristor, which has essentially the same properties as a "normal" thyristor, but in addition can be made non-conductive by applying a gate signal of opposite polarity compared to the initial gate signal for firing the GTO thyristor.

[0029] Further alternative switching devices include, but are not limited to, IGBTs, FETs, or any switching device that can be turned on and off at the appropriate time, in particular turned off after the first half wave.

[0030] If a switching device is used that actively needs to be switched off to return to a non-conducting or "OFF" state, a suitable switching circuit may be provided. This may include, for example, a (micro)controller, which may be programmed to turn the switching device on and / or off at the desired times. Alternatively, or in addition, an additional (analog) circuit may be provided to turn the switching device off depending on the voltage present at a point in the first branch, in particular the voltage present at the terminals of the switching device that is connected to the first inductor as part of the first branch.

[0031] In the sense of the present invention, the term "electrical connection" is preferably intended to be understood as meaning a connection that allows a current, in particular a current of substantial magnitude, to flow. Such an electrical connection may be achieved by a conductor such as a metal wire, but may also involve a semiconductor component in the ON state. In contrast, the term "electrical connection" is preferably not intended to cover a semiconductor component in the OFF state, even though a current (such as a reverse leakage current in a diode or thyristor) may flow through such a semiconductor component when in the OFF state. Such a reverse leakage current will typically be significantly smaller than the current that can flow when the semiconductor component is in the ON state. The phrase "electrically connect" should be understood accordingly.

[0032] In the embodiment of the first aspect, various components can be used as electric (or electronic) components or as part of an electric (or electronic) component assembly in the second branch. This includes diodes, especially diodes with pn junctions or metal-semiconductor junctions (Schottky contacts). More generally, this includes components with similar functions to diodes, including rectifiers such as electrolytic rectifiers, mercury rectifiers, plate rectifiers (metal rectifiers, especially selenium rectifiers), and vacuum tube rectifiers (vacuum tube diodes).

[0033] The components listed in the previous paragraph may be considered as passive rectifiers, i.e. rectifiers that do not require additional circuitry to affect the rectifier's behavior. Alternatively or in addition, active switching devices may be used, which can be actively switched by additional circuitry (which may be considered as part of an electric or electronic component assembly). Such circuits may include analog circuits and / or microcontrollers. Such (active) switching devices may be used in any embodiment of the invention, for example, in place of a diode in the second branch.

[0034] In one embodiment, the device further comprises a circuit for selectively bypassing or shorting the second inductor, selectively changing the inductance of the branch of which the second inductor forms part. Such a circuit for selectively bypassing or shorting the second inductor may comprise an electrical connection between two terminals of the second inductor, whereby this electrical connection comprises an additional switching device for selectively interrupting or closing this electrical connection. Assuming that a relatively low-ohmic electrical connection is used for bypassing or shorting the second inductor, the current through the branch of which the second inductor forms part flows (almost) exclusively through this bypass circuit rather than through the second inductor (when the additional switching device as part of this bypass circuit is closed). Thus, when the bypass circuit is closed, the inductance of the branch of which the second inductor forms part is reduced when compared to the situation when the bypass circuit is interrupted. This change in inductance also has the effect of changing the frequency of the resonant circuit. In particular, when current flows through the second inductor, the frequency of the resonant circuit is lower (i.e., each half-wave then has a longer duration) than when the second inductor is bypassed. Furthermore, when current flows through the second inductor, the magnitude of the current through the resonant circuit is lower than when the second inductor is bypassed.

[0035] In one embodiment, the inductance of the second inductor is: - discretely variable, and - substantially continuously variable; It is one of them.

[0036] Inductors with discretely variable or substantially continuously variable inductance are well known in the art. If the second inductor consists of a coil with a set of turns, the inductance can be varied discretely by bypassing one or more (full) turns, or by bypassing a portion of the turns (e.g., 3 / 4 or 5.375 turns). By using a variometer as the second inductor, the inductance can be varied substantially continuously. Other possible implementations of inductors with (continuously) variable inductance include inductors with a core, e.g., a coil with a set of turns wound around the core, whereby the core is (partially) introduced into or withdrawn from the coil.

[0037] In one embodiment, the apparatus further includes one or more additional inductors forming part of the branches of which the second inductor forms a part.

[0038] The additional inductor is contemplated to be connected in series with the second inductor, but could also be connected in parallel with the second inductor. By using two or more additional inductors, it is also possible to use a combination of series and parallel connections for the second inductor and the additional inductors.

[0039] In one embodiment, the apparatus further comprises a circuit for selectively bypassing or shorting the second inductor and / or one or more of the one or more additional inductors to selectively vary the inductance of the branch of which the second inductor forms a part.

[0040] The effects of bypassing or shorting the second inductor have already been described above. As an alternative to or in addition to bypassing or shorting the second inductor, bypassing or shorting one or more of the one or more additional inductors has corresponding effects, including the effect of changing the frequency of the resonant circuit and the effect of changing the magnitude of the current through the branch of which the second inductor forms part.

[0041] In one embodiment, the inductance of the second inductor and / or of at least one of the one or more additional inductors is: - discretely variable, and - substantially continuously variable; It is one of them.

[0042] Again, the inductor having a discretely variable inductance or a substantially continuously variable inductance has already been described above with respect to the second inductor, which can be applied to the one or more additional inductors as well.

[0043] The use of an inductor with a discretely or substantially continuously variable inductance may be used in conjunction with a circuit for bypassing or shorting the second inductor and / or one or more additional inductors, but may also be used without such a bypass circuit. By using an inductor with a variable inductance in combination with a bypass circuit, the device (resonant circuit) can potentially cover a wide variety of different frequencies, which may be variable in a discrete or substantially continuous manner.

[0044] In one embodiment, the inductance of the second inductor and of the one or more additional inductors is such that the inductance of the branch of which the second inductor forms part varies from a minimum value to a maximum value: - discretely variable, and - substantially continuously variable; is selected to be one of the minimum value corresponds to the inductance of the branch of which the second inductor forms part when the second inductor and the further inductor are bypassed or short-circuited; The maximum value corresponds to the inductance of the branch of which the second inductor forms a part when the second inductor and the additional inductor are not bypassed or short-circuited and the inductance of the second inductor and / or of at least one of the one or more additional inductors is at a maximum.

[0045] For example, when a second inductor and one or more additional inductors are connected in series, their inductances add to result in a (total) inductance of the branch of which the second inductor forms a part. By selectively bypassing or shorting the second inductor and / or the additional inductors, or by varying their individual inductances, the (total) inductance of each branch can be varied over a wide range.

[0046] In one embodiment, the first inductor comprises at least one set of turns, preferably at least one set of generally circular, hexagonal, or rectangular turns; some of the turns of the at least one set of turns are preferably arranged such that when a current flows through the first inductor, each turn produces a contribution towards the magnetic field, the contributions produced by each turn being superimposed in a positive manner; the first inductor is disposed within a casing connected to a conduit through which at least one cable passes for supplying power to at least one set of windings; The second inductor is not disposed within the casing.

[0047] According to this embodiment, the first inductor may be arranged in a casing, for example made of a plastic material, which may be separate from and separately movable with respect to the unit, such as a housing or cabinet, which contains the power storage device, the switching device, and the electric component or electric component assembly, as well as the first and second branches of the connection circuit. The casing containing the first inductor may be connected to the cabinet by a conduit tube, which contains a cable for supplying power to the first inductor. An arrangement in which the first inductor and the casing containing the first inductor are connected to other parts of the device by means of a conduit tube, such that the first inductor can be relatively moved with respect to such other parts, may advantageously be used to bring the first inductor close to body tissues without moving these other parts (for example the cabinet containing these other parts, which may be significantly larger and heavier than the first inductor and the casing containing the first inductor).

[0048] In one embodiment, the power storage device comprises a pulse capacitor that can be charged by a charging circuit.

[0049] The charging circuit may form part of the apparatus or may be provided as a separate device for connection to the apparatus of the first aspect. The charging circuit may in particular comprise a voltage source and a switch for selectively connecting the voltage source to the capacitor.

[0050] In a second aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a first inductor for generating a magnetic field for application to body tissue; a connection circuit between the power storage device and the first inductor, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device configured to electrically connect the power storage device to the first inductor and to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor, thereby causing the first inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the first inductor; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct electrical current primarily in a forward direction, said electrical component or electrical assembly forming part of the second branch to allow current to flow between the power storage device and the first inductor through the second branch, wherein forward current flow represents a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; The total inductance of the first branch is the sum of the total inductance of the second branch, At least 1.5 times, At least twice as many At least five times, At least 10 times, At least 50 times, At least 100 times, At least 500 times, At least 1000 times, At least 2000 times, At least 5000 times, At least 10,000 times They differ by a multiple of one of

[0051] According to the second aspect, the inventors recognize that the various components of the device are not "ideal" components in the electrical sense. For example, individual components such as the storage device, the first inductor, the switching device, the electrical components or electrical component assemblies forming part of the second branch, as well as the connecting circuitry, typically have one or more of parasitic resistances, capacitances and inductances. In particular, both the first branch and the second branch will have non-zero inductances. However, by ensuring that the inductance of the first branch differs from the inductance of the second branch by (at least) one of the above multiples, the frequencies associated with the first branch and the second branch (each in combination with the storage device and the first inductor) respectively will also be different, in particular significantly different.

[0052] The inductance difference between the first and second branches may be achieved, in particular, by including a second inductor (and potentially additional inductors) in one of the branches, as described with respect to the first embodiment.

[0053] In a third aspect of the present disclosure, there is provided a method of generating a magnetic field, the method comprising: Providing an apparatus according to a first aspect; Storing electrical energy in an electrical storage device; switching the switching device to electrically connect the power storage device to the first inductor, thereby allowing a current caused by the electrical energy stored with the power storage device to flow through the first branch and through the first inductor, thereby causing the first inductor to generate a magnetic field; and allowing current to flow through the electrical component or electrical component assembly through a second branch between the power storage device and the first inductor.

[0054] In one embodiment, the device used in the third aspect is operated in a pulsed manner, the current through the first branch representing a first half-pulse and the current through the second branch representing a second half-pulse, the duration of the second half-pulse being different from the duration of the first half-pulse.

[0055] The difference in duration of the two half-pulses is due to the difference in inductance between the first branch and the second branch, in particular because the second inductor (and any additional inductors) form part of the branches.

[0056] In one embodiment, the method further comprises selectively bypassing or shorting the second inductor or varying the inductance of the second inductor, thereby selectively varying the inductance of the branch of which the second inductor forms a part.

[0057] Bypassing or shorting the second inductor and varying the inductance of the second inductor have already been described with respect to the first embodiment.

[0058] In one embodiment, selectively bypassing or shorting the second inductor or varying the inductance of the second inductor may be performed using a method comprising: during the first half-pulse, during the second half-pulse, between the first and second half-pulses, and - Between the second half-pulse and the following pulse This includes performing the process in one of the following ways:

[0059] A suitable (switching) circuit may be used to actively bypass or short-circuit the second inductor or to vary the inductance of the second inductor. Depending on when this bypassing, short-circuiting or varying is performed, different effects may be achieved. If performed during the first half-pulse (and assuming that the second inductor forms part of the first branch), the frequency of the resonant circuit is changed during the first half-pulse and the duration of the first half-pulse is changed accordingly in the middle of the first half-pulse. Similarly, if performed during the second half-pulse (and assuming that the second inductor forms part of the second branch), the frequency of the resonant circuit is changed during the second half-pulse and the duration of the second half-pulse is changed accordingly in the middle of the second half-pulse. In both cases, the signal (e.g. the current through the first inductor) changes its shape at the point in time when the second inductor is bypassed or short-circuited or its inductance is changed. That is, it does not continue to follow the same shape of the (approximated) sine wave half-pulse it first followed, but instead continues along a different (approximated) sine wave shape (of different pulse duration). If the second inductor is bypassed or shorted, or its inductance is changed between the first and second half-pulse, the shape of each half-pulse will (approximately) resemble a sine wave half-pulse. However, the duration and amplitude of the two half-pulses will be different. The same is true, mutatis mutandis, if the second inductor is bypassed or shorted, or its inductance is changed between one (full) pulse and the next (full) pulse.

[0060] A corresponding effect can be achieved by initially bypassing or shorting the second inductor and then interrupting the bypass or short either during the first half-pulse, during the second half-pulse, between two half-pulses, or between one (full) pulse and the next (full) pulse.

[0061] In one embodiment, the method further comprises bringing a first inductor close to the body tissue or bringing the body tissue close to the first inductor such that a magnetic field is present within said body tissue.

[0062] It may in particular be used for therapeutic purposes, but also for non-therapeutic purposes.

[0063] Because the second inductor affects the frequency of the resonant circuit and the magnitude of the current through the first inductor, the second inductor also affects the magnetic field generated by the first inductor, which can be used to achieve specific effects in body tissue.

[0064] According to this embodiment, bringing the first inductor close to the body tissue can be achieved, for example, by moving the first inductor, sometimes also called an applicator coil, towards the body tissue or along the body surface of the person or animal. One example of bringing the body tissue close to the first inductor can involve using the first inductor in a (temporary) fixed position and the person or animal approaching the first inductor. Such a first inductor in a fixed position can be, for example, attached to or integrated into a chair or similar.

[0065] It is also possible to first bring the first inductor close to the body tissue (or the body tissue close to the first inductor) and then generate the magnetic field, or vice versa.

[0066] The distance between the first inductor and the body tissue may be, for example, a few millimeters or centimeters, although larger distances (such as tens of centimeters) may also be considered.

[0067] In one embodiment, the method further comprises altering a magnetic field within the body tissue to generate a voltage within the body tissue or to cause a movement of electric charge within the body tissue.

[0068] When the magnetic field in the body tissue changes with the current through the first inductor, a voltage is generated (or a transfer of charge is induced) in the body tissue passing through the magnetic field.

[0069] In one embodiment, the voltage (or charge transfer) generated in the body tissue is sufficient to induce a neural or cellular physiological response in the body tissue, particularly a muscular response, and preferably the voltage (or charge transfer) is sufficient to induce a therapeutic effect.

[0070] By using the apparatus of the first aspect or the method of the third aspect, in particular by appropriate selection of the second inductor, and, where applicable, by bypassing or shorting the second inductor or varying its inductance, various effects can be achieved in a targeted manner.

[0071] In a fourth aspect of the present disclosure, there is provided an apparatus for use with a first inductor to generate a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a terminal for connection to a first inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the power storage device and the terminal, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device electrically connecting a power storage device to the terminals and configured to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor via the terminals when a first inductor is connected to an apparatus via the terminals, thereby causing the first inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the terminals; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct current primarily in a forward direction, said electrical component or electrical assembly forming part of a second branch such that when the first inductor is connected to an apparatus via said terminals, current can flow through the second branch between the power storage device and the first inductor via said terminals, wherein forward current flow represents a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; and a second inductor, the second inductor forming part of either the first branch or the second branch.

[0072] The device of the fourth embodiment is similar to the device of the first embodiment. However, in contrast to the first embodiment, the first inductor mentioned in relation to the fourth embodiment does not form part of the device of the fourth embodiment. Instead, the device of the fourth embodiment has a terminal (such as an electrical socket or similar) for connecting to the first inductor. Thus, multiple (different) inductors, e.g., inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the fourth embodiment and used as the first inductor.

[0073] In a fifth aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a first inductor for generating a magnetic field for application to body tissue; a connection circuit between the power storage device and the first inductor, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device configured to electrically connect the power storage device to the first inductor and to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor, thereby causing the first inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the first inductor; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct electrical current primarily in a forward direction, said electrical component or electrical assembly forming part of the second branch to allow current to flow between the power storage device and the first inductor through the second branch, wherein forward current flow represents a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; the connection circuit further comprises a second inductor connected in series with the first inductor; the second inductor has a variable inductance, or the connection circuit further comprises a bypass circuit for selectively bypassing or shorting the second inductor, or the second inductor has a variable inductance, the connection circuit further comprising a bypass circuit for bypassing or short-circuiting the second inductor, Thereby, a current flowing through the first inductor and through the connecting circuit also flows through the second inductor or through the bypass circuit, regardless of whether said current flows through the first or second branch.

[0074] In some embodiments, an apparatus according to the fifth aspect can be fabricated similarly to the circuit described with respect to Figure 1. However, the addition of a second inductor in series with the first inductor results in significant differences in the structure of the apparatus as well as the operation of the apparatus, as described below.

[0075] The explanations given above with respect to the first aspect also apply analogously to the fifth aspect, in particular the storage device together with the first inductor and the connecting circuit can be considered (similar to) a resonant circuit (or LC circuit); the frequency ω0 of the resonant circuit is (approximately) determined by the values ​​of the (applicable) inductance L and capacitance C of the circuit, by ω0=1 / (√(LC)), whereby the applicable inductances include in particular the inductances of the first and second inductors; - the type of inductor used as the first inductor and / or the second inductor, - types of switching devices and methods of operating them; - the phrases "electrically connected" and "electrically connected"; - types of components that can be used as electrical (or electronic) components or as part of electrical (or electronic) component assemblies in the second branch This applies with respect to:

[0076] Similarly, details regarding the structure and operation of the bypass circuit for selectively bypassing or shorting the inductor have already been presented above with respect to embodiments of the first aspect of the present disclosure, and these details apply equally to the bypass circuit of the fifth aspect.

[0077] According to an embodiment of the present disclosure, the first inductor is intended to generate a magnetic field to be applied to body tissue, whereas the second inductor is not intended for this purpose. Of course, a magnetic field can in principle have an infinite extent, so that body tissue subjected to the magnetic field generated by the first inductor will also be subjected to the magnetic field generated by the second inductor. However, in an embodiment of the present disclosure, the effect of this can be made small, for example, by placing the second inductor at a suitable distance from the first inductor (and thus from any body tissue to which the magnetic field generated by the first inductor should be applied). Instead, the main purpose of the second inductor is to change the frequency of the resonant circuit of which the first and second inductors form part. In this way, the frequency of this resonant circuit can be changed, even though the inductance of the first inductor cannot be changed. The change in frequency can be used to affect at least one of the shape, duration, or magnitude of the current through the first inductor, in particular the current pulse through the first inductor.

[0078] In one embodiment, the inductance of the second inductor is one of discretely variable and substantially continuously variable.

[0079] Construction details of the inductor having a discretely variable or substantially continuously variable inductance have already been described with respect to the first aspect of the present disclosure.

[0080] In one embodiment, the apparatus further comprises one or more additional inductors connected in series with the second inductor.

[0081] The one or more additional inductors are also connected in series with the first inductor, and their inductance also affects the frequency of the resonant circuit of which the first and second inductors (and the one or more additional inductors) form a part.

[0082] Like the second inductor, the one or more additional inductors are not intended to generate a magnetic field for application to body tissue, and the description presented above with respect to the second inductor applies equally to the one or more additional inductors.

[0083] In one embodiment, one or more of the one or more additional inductors has a variable inductance.

[0084] The explanations presented above regarding the variable inductance of the second inductor apply equally to the additional inductor or inductors.

[0085] In one embodiment, the connection circuit further comprises an additional bypass circuit for selectively bypassing or shorting one or more of the one or more additional inductors.

[0086] Details regarding the structure and operation of the bypass circuit for selectively bypassing or shorting the inductor have already been presented above with respect to the embodiments of the first aspect of the present disclosure, and these details apply equally to the additional bypass circuit for selectively bypassing or shorting the one or more additional inductors of the embodiments of the fifth aspect.

[0087] In one embodiment, the additional bypass circuit comprises separate circuit portions for individually selectively bypassing or shorting one or more of the one or more additional inductors.

[0088] With such separate circuit portions, one or more particular ones of the additional inductors may be individually bypassed or shorted, while one or more other ones of the additional inductors are not bypassed or shorted. In this manner, the total inductance of the circuit of which the first, second and additional inductors form a part may take on a variety of different values.

[0089] In one embodiment, one or more of the one or more additional inductors have a variable inductance and / or comprise an additional bypass circuit for selectively bypassing or shorting a respective one of the one or more additional inductors.

[0090] In this manner, the total inductance of the circuit of which the first, second and further inductors form part can be varied over a wide range.

[0091] In one embodiment, the inductance of the second inductor and of the one or more additional inductors is such that the total inductance of the connecting circuit is, from a minimum value to a maximum value: - discretely variable, and - substantially continuously variable; is selected to be one of the minimum value corresponds to a total inductance of the connection circuit when all of the second and additional inductors comprising the additional bypass circuit are bypassed or short-circuited, and the inductances of all of the second and additional inductors whose inductances are variable are adjusted to the minimum value; The maximum value corresponds to the total inductance of the connection circuit when all of the second and additional inductors comprising the additional bypass circuit are neither bypassed nor short-circuited, and the inductances of all of the second and additional inductors whose inductance is variable are adjusted to the maximum value.

[0092] This allows the total inductance of the circuit, and therefore the frequency of the circuit, to be varied over a particularly wide range, through which the current through the first inductor can be varied accordingly. In particular, the shape, magnitude and / or duration of the current pulse through the first inductor can be varied over a correspondingly wide range.

[0093] In one embodiment, the second inductor has a variable inductance with a maximum inductance of L2, and the one or more additional inductors have an inductance of value Lm, where m=3, 4, 5, . . . n+2, n being the number of additional capacitors, and Lm being L2×2 (m-3) is essentially equal to

[0094] In this embodiment, the ratio of L2:L3:Lm is substantially 1:1:2:4:8:16, etc. Through this selection of values, the total inductance of the connection circuit can be varied from a minimum to a maximum value with a relatively small total number of inductors. If at least one of the inductors, e.g., the second inductor, has a substantially continuously variable inductance, the total inductance of the connection circuit can also be varied substantially continuously from its minimum to its maximum value.

[0095] In one embodiment, the first inductor comprises at least one set of turns, preferably at least one set of generally circular, hexagonal, or rectangular turns; some of the turns of the at least one set of turns are preferably arranged such that when a current flows through the first inductor, each turn produces a contribution towards the magnetic field, the contributions produced by each turn being superimposed in a positive manner; the first inductor is disposed within a casing connected to a conduit through which at least one cable passes for supplying power to at least one set of windings; The second inductor is not disposed within the casing.

[0096] In this embodiment, as in the corresponding embodiment of the first aspect, the first inductor may be disposed in a casing, for example made of a plastic material, which may be separate from and separately movable with respect to a unit, such as a housing or cabinet, which contains the power storage device, the switching device, and the electrical component or electrical component assembly, the first and second branches of the connection circuit, and the second inductor (and also additional inductors, if provided). The casing containing the first inductor may be connected to the cabinet by a conduit tube, which contains a cable for supplying power to the first inductor. An arrangement in which the first inductor and the casing containing the first inductor are connected to other parts of the device by means of a conduit tube, such that the first inductor can be relatively moved with respect to such other parts, may advantageously be used to bring the first inductor close to body tissue without moving these other parts (e.g. the cabinet containing these other parts, which may be significantly larger and heavier than the first inductor and the casing containing the first inductor).

[0097] In one embodiment, the power storage device comprises a pulse capacitor that can be charged by a charging circuit.

[0098] The charging circuit may form part of the apparatus or may be provided as a separate device for connection to the apparatus of the fifth aspect. The charging circuit may in particular comprise a voltage source and a switch for selectively connecting the voltage source to the capacitor.

[0099] In a sixth aspect of the present disclosure, there is provided a method of generating a magnetic field, the method comprising: Providing an apparatus according to a fifth aspect; Storing electrical energy in an electrical storage device; Switching the switching device to electrically connect the power storage device to the first inductor, whereby a current caused by the electrical energy stored using the power storage device is - the first branch, and a first inductor, and - A second inductor or bypass circuit thereby causing the first inductor to generate a magnetic field; and The current through a second branch via said electrical component or electrical component assembly, through a second inductor or bypass circuit, and allowing current to flow between the power storage device and the first inductor.

[0100] In one embodiment, the device is operated in a pulsed manner, where current through the first branch represents a first half-pulse and current through the second branch represents a second half-pulse, the first half-pulse and the second half-pulse together forming one pulse.

[0101] Assuming that the inductances of the first and second branches are (at least approximately) the same, the duration and magnitude of the first and second half-pulses will be (at least approximately) the same, although as explained above the magnitude of the second half-pulse may be somewhat smaller than the magnitude of the first half-pulse due to energy losses in the circuit. However, if the inductances of the first and second branches are not the same (especially if they are substantially different), the duration and magnitude of the first half-pulse will be (significantly) different from the duration and magnitude of the second half-pulse. This may be the case when an additional inductor is connected in series with either the switching device or the electrical component or electrical component assembly, such that a current flows in the additional inductor during the first half-pulse but not during the second half-pulse, or vice versa.

[0102] In one embodiment, the method further includes selectively bypassing or shorting the second inductor or varying the inductance of the second inductor, thereby selectively varying the inductance of the connecting circuit.

[0103] Bypassing or shorting the second inductor and varying the inductance of the second inductor have already been described with respect to the fifth embodiment.

[0104] In one embodiment, selectively bypassing or shorting the second inductor or varying the inductance of the second inductor may be performed using a method comprising: during the first half-pulse, during the second half-pulse, between the first and second half-pulses, and - After the pulse This includes performing the process in one of the following ways:

[0105] A suitable (switching) circuit may be used to actively bypass or short the second inductor or to vary the inductance of the second inductor. Depending on when this bypassing, shorting or varying is performed, different effects may be achieved. If performed during the first half-pulse, the frequency of the resonant circuit is changed during the first half-pulse and the duration of the first half-pulse is changed accordingly in the middle of the first half-pulse. Similarly, if performed during the second half-pulse, the frequency of the resonant circuit is changed during the second half-pulse and the duration of the second half-pulse is changed accordingly in the middle of the second half-pulse. In both cases, the signal (e.g. the current through the first inductor) changes its shape at the point when the second inductor is bypassed or shorted or its inductance is changed. That is, it does not continue to follow the same shape of the (approximated) sine wave half-pulse that it initially followed, but instead continues along a different (approximated) sine wave shape (of different pulse duration). If the second inductor is bypassed or shorted, or its inductance is changed between the first and second half-pulses, the shape of each half-pulse will (approximately) resemble a sinusoidal half-pulse. However, the duration and amplitude of the two half-pulses will be different. The same is true, mutatis mutandis, if the second inductor is bypassed or shorted, or its inductance is changed between one (full) pulse and the next (full) pulse.

[0106] A corresponding effect can be achieved by initially bypassing or shorting the second inductor and then interrupting the bypass or short either during the first half-pulse, during the second half-pulse, between two half-pulses, or between one (full) pulse and the next (full) pulse.

[0107] In one embodiment, the method further comprises bringing a first inductor close to the body tissue or bringing the body tissue close to the first inductor such that a magnetic field is present within said body tissue.

[0108] As with the third aspect, this may in particular be used for therapeutic purposes, but may also be used for non-therapeutic purposes.

[0109] The further explanations given with respect to the corresponding embodiment of the third aspect also apply to this embodiment of the sixth aspect.

[0110] In one embodiment, the method further comprises altering a magnetic field within the body tissue to generate a voltage within the body tissue or to cause a movement of electric charge within the body tissue.

[0111] When the magnetic field in the body tissue changes with the current through the first inductor, a voltage is generated (or a transfer of charge is induced) in the body tissue passing through the magnetic field.

[0112] In one embodiment, the voltage (or charge transfer) generated in the body tissue is sufficient to induce a neural or cellular physiological response, particularly a muscular response, in the body tissue; Preferably, the voltage (or charge transfer) is sufficient to cause a therapeutic effect.

[0113] By using the apparatus of the fifth aspect or the method of the sixth aspect, in particular by appropriate selection of the second inductor, and, where applicable, by bypassing or shorting the second inductor or varying the inductance, various effects can be achieved in a targeted manner.

[0114] In a seventh aspect of the present disclosure, there is provided an apparatus for use with a first inductor to generate a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a terminal for connection to a first inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the power storage device and the terminal, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device electrically connecting a power storage device to the terminals and configured to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor via the terminals when a first inductor is connected to an apparatus via the terminals, thereby causing the first inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the terminals; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct electrical current primarily in a forward direction, said electrical component or electrical assembly forming part of a second branch such that when the first inductor is connected to an apparatus via said terminals, current can flow through the second branch between the power storage device and the first inductor via said terminals, wherein forward current flow represents a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; the connection circuit further comprises a second inductor connected in series with the first inductor; the second inductor has a variable inductance, or the connection circuit further comprises a bypass circuit for selectively bypassing or shorting the second inductor, or the second inductor has a variable inductance, the connection circuit further comprising a bypass circuit for bypassing or short-circuiting the second inductor, Thereby, a current flowing through the first inductor and through the connecting circuit also flows through the second inductor or through the bypass circuit, regardless of whether said current flows through the first or second branch.

[0115] The device of the seventh embodiment is similar to the device of the fifth embodiment. However, in contrast to the fifth embodiment, the first inductor mentioned in relation to the seventh embodiment does not form part of the device of the fourth embodiment. Instead, the device of the seventh embodiment has a terminal (such as an electrical socket or similar) for connecting to the first inductor. Thus, multiple (different) inductors, e.g. inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the seventh embodiment and used as the first inductor.

[0116] In an eighth aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a capacitor arrangement comprising at least one capacitor for storing electrical energy; an inductor for generating a magnetic field for application to body tissue; a connection circuit between the capacitor arrangement and the inductor, the connection circuit having at least a first branch and a second branch; a first switching device forming part of the first branch, the first switching device configured to electrically connect the capacitor arrangement to the inductor and to allow a current caused by electrical energy stored using the capacitor arrangement to flow through the first branch and through the inductor, thereby causing the inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the capacitor arrangement and the inductor; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct current primarily in a forward direction, said electrical component or electrical assembly forming part of a second branch such that current can flow through the second branch between the capacitor arrangement and the inductor, wherein forward current flow represents a second current direction of current flow between the capacitor arrangement and the inductor, the second current direction being opposite to the first current direction; The capacitor has a variable capacitance.

[0117] In some embodiments, a device according to the eighth aspect can be fabricated similarly to the circuit described with respect to Figure 1. However, the use of a capacitor with variable capacitance results in significant differences in the structure of the device as well as in the operation of the device, as described below.

[0118] The explanations given above with respect to the first and fifth aspects also apply analogously to the eighth aspect, in particular the capacitor arrangement of the eighth aspect (comprising at least one capacitor), which is a form of power storage device (first and fifth aspects), together with the inductor and the connecting circuit, can be considered (similar to) a resonant circuit (or LC circuit); the frequency ω0 of the resonant circuit is (approximately) determined by the values ​​of the (applicable) inductance L and capacitance C of the circuit, according to ω0=1 / (√(LC)), whereby the applicable inductance includes in particular the inductance of the first inductor (and of any second or additional inductors); - type of inductor for use as inductor, - types of switching devices and methods of operating them; - the phrases "electrically connected" and "electrically connected"; - types of components that can be used as electrical (or electronic) components or as part of electrical (or electronic) component assemblies in the second branch This applies with respect to:

[0119] In principle, any type of variable capacitor (or capacitor with variable capacitance) may be used as a capacitor in the eighth aspect, including mechanically controlled variable capacitors and electrically controlled variable capacitors. The capacitance of the at least one capacitor affects the frequency of the resonant circuit of which it forms part, i.e. by varying the capacitance of the at least one capacitor, the frequency of the resonant circuit is also varied, as explained above.

[0120] In some embodiments, the capacitance of at least one capacitor is (substantially) continuously variable. In this way, the frequency of the resonant circuit is also (substantially) continuously variable. Alternatively, the capacitance of at least one capacitor is discretely variable, preferably, however, in small steps. In this way, the frequency of the resonant circuit can be almost continuously variable.

[0121] In one embodiment, the capacitor arrangement comprises one or more additional capacitors connected in parallel to said capacitor, the capacitance of which affects the frequency of a resonant circuit of which the capacitor and the one or more additional capacitors form part.

[0122] In one embodiment, at least one of the one or more additional capacitors, in particular all of the additional capacitors, - it is mutable, - discretely variable, and - substantially continuously variable; The capacitance of the capacitor is either

[0123] This also helps to ensure that the frequency of the resonant circuit of which the capacitor and the one or more additional capacitors form part can be adjusted The wider the adjustable range of the capacitance of the capacitor and the one or more additional capacitors, the wider the adjustable range of the frequency of the resonant circuit, thereby providing greater flexibility with respect to the magnetic fields generated by the device, such as the pulse duration, amplitude and / or shape of the pulses.

[0124] In one embodiment, the capacitance of the first capacitor and the capacitance of the one or more additional capacitors are such that the total capacitance of the capacitor arrangement is, from a minimum value to a maximum value: - discretely variable, and - substantially continuously variable; is selected to be one of the minimum value corresponds to a total capacitance of the capacitor arrangement when the capacitance of the first capacitor and the capacitance of the one or more additional capacitors are adjusted to the minimum value; The maximum value corresponds to the total capacitance of the capacitor arrangement when the capacitance of the first capacitor and the capacitance of the one or more additional capacitors are adjusted to the maximum value.

[0125] Since the capacitor and the one or more additional capacitors are connected in parallel, their capacitances are added together, resulting in the total capacitance of the resonant circuit of which the capacitor and the one or more additional capacitors form part (again assuming ideal components). In particular, if the capacitances of all capacitors, the first capacitor and the one or more additional capacitors, are (substantially) continuously variable, the total capacitance is also (substantially) continuously variable from the above-mentioned minimum to maximum value. However, even if only the capacitance of one capacitor is (substantially) continuously variable and the capacitance of the additional capacitors is only discretely variable, the total capacitance may still be (substantially) continuously variable from the above-mentioned minimum to maximum value. This is in particular the case where the discrete steps in which the capacitance of such additional capacitors is variable are not wider than the range in which the capacitance of the (first) capacitor is (substantially) continuously variable. As an example, let us assume that the capacitance of the first capacitor is (substantially) continuously adjusted between 0 μF and 100 μF and that the capacitance of one additional capacitor may be adjusted in discrete steps to take only two values, 0 μF and 100 μF. In this case, when the additional capacitor is adjusted to 0 μF, by changing the capacitance of the first capacitor, the total capacitance of the capacitor arrangement can be adjusted (substantially) continuously between 0 μF and 100 μF. When the additional capacitor is adjusted to 100 μF, by changing the capacitance of the first capacitor, the total capacitance of the capacitor arrangement can be adjusted (substantially) continuously between 100 μF and 200 μF. Thus, the total capacitance of the capacitor arrangement can be adjusted (substantially) continuously between 0 μF and 200 μF. Similarly, in another example, if the additional capacitor is adjusted in discrete steps to take values ​​of 200 μF, 300 μF, and 400 μF, and the capacitance of the first capacitor can be adjusted (substantially) continuously between 0 μF and 100 μF, the total capacitance of the capacitor arrangement can be adjusted (substantially) continuously between 200 μF and 500 μF.

[0126] In one embodiment, the apparatus further comprises one or more additional switching devices, one for each of the one or more additional capacitors, the one or more additional switching devices configured to selectively interrupt an electrical connection between a respective one of the one or more additional capacitors and the connection circuit.

[0127] In this manner, the total capacitance of the circuit of which the first capacitor and the one or more additional capacitors form part can take on a variety of different values.

[0128] It is also possible to provide some of the additional capacitors with respective additional switching devices and other of the additional capacitors as capacitors having variable capacitance, in which case the total capacitance of the circuit may also take on a variety of different values ​​and in particular be adjustable (substantially continuously) over a selected range.

[0129] In one embodiment, the capacitance of the first capacitor and the capacitance of the one or more additional capacitors are such that the total capacitance of the capacitor arrangement is, from a minimum value to a maximum value: - discretely variable, and - substantially continuously variable; is selected to be one of The minimum value is the total capacitance of the capacitor arrangement. the electrical connection between the one or more additional capacitors and the connection circuit is interrupted by an additional switching device, when the capacitance of the first capacitor is adjusted to its minimum value, Corresponding, The maximum value depends on the total capacitance of the capacitor arrangement. the electrical connection between the one or more additional capacitors and the connection circuit is not interrupted, when the capacitance of the first capacitor is adjusted to its maximum value, handle.

[0130] The above statements regarding the tunability of the total capacitance of the capacitor arrangement also apply mutatis mutandis to this embodiment.

[0131] In one embodiment, the apparatus further comprises a charging circuit for charging the capacitor arrangement.

[0132] The charging circuit may in particular comprise a voltage source and a switch for selectively connecting the voltage source to the capacitor arrangement.

[0133] In an alternative embodiment, the charging circuitry may be provided as a separate device for connection to the apparatus of the eighth aspect, ie it may not form part of the apparatus of the eighth aspect.

[0134] In one embodiment, the first capacitor has a maximum capacitance of value C1, the n additional capacitors have a capacitance of value Cm, n being the number of additional capacitors, m=2, 3, 4, ..., n+1; - Cm is C1×2 (m-2) is essentially equal to

[0135] In this embodiment, the ratio of C1:C2:Cm is substantially 1:1:2:4:8:16 etc. Through this selection of values, the total capacitance of the capacitor arrangement can be varied from a minimum to a maximum value over a relatively wide range with a relatively small total number of capacitors. If at least one of the capacitors, e.g. the first capacitor, has a capacitance that is (substantially) continuously variable, the total capacitance of the capacitor arrangement can also be varied (substantially) continuously from its minimum to its maximum value.

[0136] In a ninth aspect of the present disclosure, there is provided a method of generating a magnetic field, the method comprising: Providing an apparatus according to an eighth aspect; storing electrical energy in a capacitor arrangement; switching a first switching device to electrically connect the capacitor arrangement to the inductor, thereby allowing a current caused by electrical energy stored with the capacitor arrangement to flow through the first branch and through the first inductor, thereby causing the inductor to generate a magnetic field; allowing current to flow through the electrical component or electrical component assembly through a second branch between the capacitor arrangement and the inductor.

[0137] In one embodiment, the device is operated in a pulsed manner, with current through the first branch representing a first half-pulse and current through the second branch representing a second half-pulse.

[0138] As mentioned above, the pulse, and in particular its duration, amplitude and / or shape, may be influenced by varying the capacitance of the capacitor arrangement.

[0139] In one embodiment, the method includes varying the total capacitance of the capacitor arrangement. during the first half-pulse, during the second half-pulse, between the first and second half-pulses, and - Between the second half-pulse and the following pulse The method further includes performing the method at any time among the steps of

[0140] Suitable arrangements for varying the total capacitance of the capacitor arrangement have already been described above and include in particular varying the capacitance of individual capacitors of the capacitor arrangement and / or selectively establishing or breaking an electrical connection between each of the one or more additional capacitors and the connecting circuit using one or more additional switching devices for each of the one or more additional capacitors.

[0141] Depending on when the change in the total capacitance of the capacitor arrangement is performed, different effects may be achieved: if it is performed during the first half-pulse, the frequency of the resonant circuit is changed during the first half-pulse and the duration of the first half-pulse is changed accordingly in the middle of the first half-pulse. Similarly, if it is performed during the second half-pulse, the frequency of the resonant circuit is changed during the second half-pulse and the duration of the second half-pulse is changed accordingly in the middle of the second half-pulse. In both cases, the signal (e.g. the current through the inductor) changes its shape at the time when the total capacitance of the capacitor arrangement is changed. That is, the signal does not continue to follow the same shape of the (approximated) sinusoidal half-pulse that it first followed, but instead continues along a different (approximated) sinusoidal shape (of different pulse duration). If the change in the total capacitance of the capacitor arrangement occurs between the first and second half-pulses, the shape of each half-pulse resembles (approximately) a sinusoidal half-pulse. However, the duration and amplitude of the two half-pulses are different. The same is true mutatis mutandis when a change in the total capacitance of the capacitor arrangement occurs between one (full) pulse and the next (full) pulse.

[0142] In one embodiment, the total capacitance of the capacitor arrangement is changed such that the duration of the second half-pulse is longer than the duration of the first half-pulse. This may be achieved by increasing the total capacitance of the capacitor arrangement between the first and second half-pulses, or any time after the start of the first half-pulse and before the end of the second half-pulse.

[0143] Depending on whether the total capacitance of the capacitor arrangement is increased or decreased, different effects can be achieved. This can be increased by increasing the capacitance of the individual capacitors of the capacitor arrangement or by activating one or more additional switching devices to establish an electrical connection between each one of the one or more additional capacitors and the connection circuit. Conversely, this can be decreased by decreasing the capacitance of the individual capacitors of the capacitor arrangement or by activating one or more additional switching devices to interrupt the electrical connection between each one of the one or more additional capacitors and the connection circuit. Increasing the total capacitance of the capacitor arrangement results in a longer pulse duration. Reducing the total capacitance of the capacitor arrangement results in a shorter pulse duration.

[0144] In one embodiment, the method further comprises bringing an inductor into proximity with the body tissue so as to generate a magnetic field within the body tissue, or bringing the body tissue into proximity with an inductor so as to have a magnetic field present within the body tissue.

[0145] It may in particular be used for therapeutic purposes, but also for non-therapeutic purposes.

[0146] Because the total capacitance of the capacitor arrangement affects the frequency of the resonant circuit and the magnitude of the current through the inductor, the total capacitance also affects the magnetic field generated by the inductor, which can be used to achieve specific effects in body tissue.

[0147] According to this embodiment, bringing the inductor close to the body tissue can be achieved, for example, by moving the inductor, sometimes also called an applicator coil, towards the body tissue or along the body surface of the person or animal. One example of bringing the body tissue close to the inductor can involve using the inductor in a (temporary) fixed position and the person or animal approaching the inductor. Such a fixed-position inductor can be, for example, attached to or integrated into a chair or similar.

[0148] It is also possible to first bring the inductor close to the body tissue (or vice versa) and then generate the magnetic field, or vice versa.

[0149] The distance between the inductor and the body tissue may be, for example, a few millimeters or centimeters, although larger distances (such as tens of centimeters) are also contemplated.

[0150] In one embodiment, the method further comprises altering a magnetic field within the body tissue to generate a voltage within the body tissue or to cause a movement of electric charge within the body tissue.

[0151] When the magnetic field in the body tissue changes with the current through the inductor, a voltage is generated (or a movement of charge is induced) in the body tissue passing through the magnetic field.

[0152] In one embodiment, the voltage (or charge transfer) generated in the body tissue is sufficient to induce a neural or cellular physiological response, particularly a muscular response, in the body tissue; Preferably, the voltage (or charge transfer) is sufficient to cause a therapeutic effect.

[0153] Using the apparatus of the eighth aspect or the method of the ninth aspect, various effects may be achieved in a targeted manner, in particular by suitable selection of the total capacitance of the capacitor arrangement, in particular by suitable selection of the capacitance of the individual capacitors of the capacitor arrangement, and / or, where applicable, by actuating one or more additional switching devices to establish or interrupt an electrical connection between a respective one or more of the additional capacitors and a connecting circuit.

[0154] In a tenth aspect of the present disclosure, there is provided an apparatus for use with an inductor to generate a magnetic field for application to body tissue, the apparatus comprising: a capacitor arrangement comprising at least one capacitor for storing electrical energy; a terminal for connecting to an inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the capacitor arrangement and the terminal, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device electrically connecting a capacitor arrangement to the terminal and configured to allow a current caused by electrical energy stored using the capacitor arrangement to flow through the first branch and through the inductor via the terminal when an inductor is connected to an apparatus via the terminal, thereby causing the inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the capacitor arrangement and the terminal; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct current primarily in a forward direction, said electrical component or electrical assembly forming part of a second branch such that current can flow through the second branch between a capacitor arrangement and the inductor via said terminals when the inductor is connected to a device via said terminals, wherein forward current flow represents a second current direction of current flow between the capacitor arrangement and the inductor, the second current direction being opposite to the first current direction, The capacitor has a variable capacitance.

[0155] The device of the tenth embodiment is similar to the device of the eighth embodiment. However, in contrast to the eighth embodiment, the inductor mentioned in relation to the eighth embodiment does not form part of the device of the tenth embodiment. Instead, the device of the tenth embodiment has a terminal (such as an electrical socket or similar) for connecting to the inductor. Thus, multiple (different) inductors, e.g., inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the tenth embodiment and used as inductors.

[0156] In an eleventh aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a capacitor arrangement comprising at least one capacitor for storing electrical energy; an inductor for generating a magnetic field for application to body tissue; a connection circuit between the capacitor arrangement and the inductor, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device configured to switch from a substantially non-conducting state to a conducting state at a first time to form a first electrical connection between the capacitor arrangement and the inductor and allow a current caused by electrical energy stored with the capacitor arrangement to flow through the first branch and through the inductor, thereby causing the inductor to generate a magnetic field, and the switching device configured to switch from a conducting state to a substantially non-conducting state at a second time to interrupt the first electrical connection between the capacitor arrangement and the inductor; at least one electrical circuit element forming part of the second branch, the electrical circuit element configured to switch from a substantially non-conducting state to a conducting state to form a second electrical connection between the capacitor arrangement and the inductor and allow current to flow through the second branch and through the inductor; The first and second time points can be freely selected.

[0157] In some embodiments, the apparatus according to the eleventh aspect can be fabricated similarly to the circuit described with respect to Figure 1. However, the fabrication of the apparatus in which the switching device can be switched from a substantially non-conducting state to a conducting state and back to a substantially non-conducting state at first and second freely selectable times, respectively, presents significant differences with respect to not only the structure of the apparatus, but also the operation of the apparatus, as will be explained below.

[0158] The explanations given above with respect to the first, fifth and eighth aspects also apply to the eleventh aspect, in particular the capacitor arrangement of the eleventh aspect (comprising at least one capacitor), which is a form of power storage device (first and fifth aspects), together with the inductor and the connecting circuit, can be considered as (similar to) a resonant circuit (or LC circuit); the capacitor arrangement of the eleventh aspect may be configured similarly to the capacitor arrangement of the eighth aspect; the frequency ω0 of the resonant circuit is (approximately) determined by the values ​​of the (applicable) inductance L and capacitance C of the circuit, according to ω0=1 / (√(LC)), whereby the applicable inductance includes in particular the inductances of the (first inductor and any second or additional inductors); - type of inductor for use as inductor, - types of switching devices and methods of operating them, subject to further details as described below; - the phrases "electrically connected" and "electrically connected"; This applies in respect of:

[0159] According to the eleventh aspect, the phrase "freely selected" does not necessarily mean that there is no restriction at all, but at least there is a significant (time) range within which the first and second time points may be selected, particularly by a user of the device. In particular, the second time point does not have to be at a specific fixed time delay after the first time point, such as after the first half-pulse or at the end of the half-pulse -- assuming that the device operates in a pulsed manner. Instead, the second time point may be selected independently of the first time point.

[0160] In a typical embodiment contemplated by the inventors, the user will preselect the first and second time points, either as specific (or absolute) time points or with respect to another event. In particular, the user may select the second time point as a time point after a selected time interval has elapsed from the first time point. For this purpose, the device may have a suitable interface, such as a dial or touch screen, via which the user can specify the selected time interval.

[0161] In one embodiment, the apparatus further comprises a first controller for causing the switching device to switch from a substantially non-conducting state to a conducting state at a first time and / or for causing the switching device to switch from a conducting state to a substantially non-conducting state at a second time. The first controller may receive a suitable input from a user, for example via the above-mentioned interface. The first controller may comprise, for example, a microcontroller. Alternatively, the first controller may be provided in the form of an analog circuit, for example in the form of a circuit connecting the above-mentioned interface (e.g. a dial) to the switching device.

[0162] In one embodiment, at least one electrical circuit element is configured to be switched from a conductive state to a substantially non-conductive state to interrupt the second electrical connection between the power storage device and the inductor.

[0163] In one embodiment, the device further comprises a second controller for causing at least one electric circuit element to switch from a substantially non-conducting state to a conducting state at a third time and / or for causing at least one electric circuit element to switch from a conducting state to a substantially non-conducting state at a fourth time. The second controller may receive a suitable input from a user, for example via an interface, such as the interface described above. The second controller may comprise, for example, a microcontroller. Alternatively, the second controller may be provided in the form of an analog circuit, for example in the form of a circuit connecting the interface (e.g. a dial) described above to the at least one electric circuit element. The second controller may be identical to the first controller in the sense that there is only one controller that controls both the switching device and the at least one electric circuit element. Alternatively, the first and second controllers may be provided as separate units.

[0164] In one embodiment, the switching device includes an insulated gate bipolar transistor (IGBT), a field effect transistor (FET), a metal oxide semiconductor field effect transistor (MOSFET), or a gate turn-off thyristor (GTO thyristor). Any other suitable switching device, particularly a device that can be switched off at a desired time, may be used instead.

[0165] In one embodiment, at least one electrical circuit element includes a passive electrical circuit element, particularly, - a spark gap, - a transient voltage suppression diode, - a Zener diode, - a Schottky diode, or - an alternating current triode (TRIAC), or - a thyristor, particularly used in combination with a trigger circuit connected to a second branch or forming part of a second branch to trigger the thyristor.

[0166] In the case of a spark gap, the setting with respect to the voltage (absolute value) involved is preferably observed. The capacitor arrangement component is charged up to, or can be charged up to, or is arranged to be charged up to the voltage U1. The spark gap is rated at the voltage U2, i.e., becomes conductive at the voltage U2. The switching device is damaged (significantly) or destroyed at a voltage U3 or higher, where U1 < U2 < U3. By following this setting, it can be ensured that the spark gap is not already in the conductive state when the capacitor arrangement component is charged. At the same time, since the voltage determined to cause the spark gap to become conductive can also be applied (in reverse bias) to the switching device, it can be ensured that the switching device (in the first branch) is not damaged or destroyed.

[0167] In one embodiment, the at least one electrical circuit element includes an active electrical circuit element or arrangement of circuit elements, particularly a switching element controlled by an analog circuit or a microcontroller, which allows a user to actively control the electrical circuit element, rather than the electrical circuit element being merely allowed to become conductive or non-conductive in response to a voltage applied to two terminals in the second branch.

[0168] A resistor may also be provided in the second branch.

[0169] In one embodiment, the at least one electrical circuit element is configured to switch from a substantially non-conductive state to a conductive state at a third time point, the third time point coinciding with or being a predetermined or predeterminable time interval after the second time point, in particular after the second time point. Again, the user may specify the third time point, for example via the interface described above, in particular the time interval between the second and third time points. Alternatively, the third time point may be fixed, or the interval between the second and third time points may be fixed.

[0170] In a twelfth aspect of the present disclosure, a method of generating a magnetic field is provided, the method comprising: Providing an apparatus according to an eleventh aspect; storing electrical energy in a capacitor arrangement; switching the switching device from a substantially non-conductive state to a conductive state at a first time to form the first electrical connection between the capacitor arrangement and the inductor, thereby allowing a current caused by electrical energy stored with the capacitor arrangement to flow through the first branch and through the inductor, thereby causing the inductor to generate a magnetic field; switching the switching device from a conductive state to a substantially non-conductive state at a second time, thereby interrupting the first electrical connection between the capacitor arrangement and the inductor; causing at least one electrical circuit element to switch from a substantially non-conductive state to a conductive state, thereby allowing current to flow through the at least one electrical circuit element through the second branch between the capacitor arrangement and the inductor.

[0171] The embodiments described with respect to the eleventh aspect apply equally to the twelfth aspect and vice versa.

[0172] In one embodiment, switching the switching device from a substantially non-conducting state to a conducting state at a first time triggers an oscillation of a current flowing between the capacitor arrangement and the inductor, and the second time is selected to not coincide with a transition between a first and a second half-wave of the oscillation, in this way the oscillation can be interrupted at a selected time to achieve a particular effect.

[0173] In one embodiment, the second point in time is selected during the first half wave of said oscillation, preferably during the first quarter wave of said oscillation.

[0174] In one embodiment, the method further comprises bringing an inductor close to the body tissue or bringing the body tissue close to the inductor such that a magnetic field is present within said body tissue, which may be used in particular for therapeutic purposes, but may also be used for non-therapeutic purposes.

[0175] Bringing the inductor close to the body tissue may be accomplished, for example, by moving the inductor, sometimes also called an applicator coil, towards the body tissue or along the body surface of the person or animal. One example of bringing the body tissue close to the inductor may involve using the inductor in a (temporary) fixed location and the person or animal approaching the inductor. Such a fixed location inductor may, for example, be attached to or integrated into a chair or similar.

[0176] It is also possible to first bring the inductor close to the body tissue (or vice versa) and then generate the magnetic field, or vice versa.

[0177] The distance between the inductor and the body tissue may be, for example, a few millimeters or centimeters, although larger distances (such as tens of centimeters) are also contemplated.

[0178] In one embodiment, the method further includes varying a magnetic field in the body tissue to generate a voltage in the body tissue or to cause a movement of charge in the body tissue. When the magnetic field in the body tissue changes with the current through the inductor, a voltage is generated (or a movement of charge is caused) in the body tissue passing through the magnetic field.

[0179] In one embodiment, the voltage (or charge transfer) generated in the body tissue is sufficient to induce a neural or cellular physiological response, particularly a muscular response, in the body tissue; Preferably, the voltage (or charge transfer) is sufficient to cause a therapeutic effect.

[0180] Using the device of the eleventh aspect or the method of the twelfth aspect, in particular by suitable selection of the first and / or second time points, in particular the time interval between the first and second time points, various effects can be achieved in a targeted manner.

[0181] In one embodiment, the method further comprises bringing an inductor into proximity with the body tissue to generate a magnetic field within said body tissue, wherein a duration between the first time point and the second time point defines a time interval, and the method further comprises: Varying the time interval; switching a switching device from a substantially non-conductive state to a conductive state; and switching the switching device from a conductive state to a substantially non-conductive state after the time interval has been varied.

[0182] By varying the time interval and switching the switching device from a conducting state to a substantially non-conducting state after the time interval is varied, the oscillations are interrupted at different times based on the varied time interval. Various measurements, particularly measurements relating to any reactions in the body tissue, may be performed, recorded and / or analyzed, particularly as a function of the variation in the time interval.

[0183] In one embodiment, the method includes detecting whether a muscle response is evoked in the body tissue to provide a detection result; and determining a minimum duration corresponding to a time interval or a changed time interval during which a muscle response in the body tissue is elicited based on the detection result.

[0184] In a thirteenth aspect of the present disclosure, there is provided an apparatus for use with an inductor to generate a magnetic field for application to body tissue, the apparatus comprising: a capacitor arrangement comprising at least one capacitor for storing electrical energy; a terminal for connecting to an inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the capacitor arrangement and the terminal, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device configured to switch from a substantially non-conducting state to a conducting state at a first time to form a first electrical connection between a capacitor arrangement and the terminal and to allow a current caused by electrical energy stored using the capacitor arrangement to flow through the first branch via the terminal and through an inductor when the inductor is connected to an apparatus via the terminal, thereby causing the inductor to generate a magnetic field, and the switching device configured to switch from a conducting state to a substantially non-conducting state at a second time to interrupt the first electrical connection between the capacitor arrangement and the terminal; at least one electrical circuit element forming part of a second branch, the electrical circuit element configured to switch from a substantially non-conducting state to a conducting state to form a second electrical connection between the capacitor arrangement and the terminal to allow current to flow through the second branch via the terminal and through the inductor when the inductor is connected to the device via the terminal; The first and second time points can be freely selected.

[0185] The device of the thirteenth aspect is similar to the device of the eleventh aspect. However, in contrast to the eleventh aspect, the inductor mentioned in relation to the thirteenth aspect does not form part of the device of the thirteenth aspect. Instead, the device of the thirteenth aspect has a terminal (such as an electrical socket or similar) for connecting to the inductor. Thus, multiple (different) inductors, e.g., inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the thirteenth aspect and used as inductors.

[0186] In any of the eleventh to thirteenth aspects or embodiments thereof, the first and second time points (or the time interval between them) may also be predetermined, i.e. preselected by a user or manufacturer and stored in a memory device of the apparatus, or may be predetermined by the electrical design (analog circuit design) of the apparatus--but again, this means that the first and second time points do not coincide with the end of the first half-pulse (again, assuming that the apparatus is operated in a pulsed manner). When the apparatus of the eleventh or thirteenth aspect is used or the method according to the twelfth aspect is performed, information regarding the first and / or second time points, or the time interval between them, may be retrieved (e.g. from a memory device) and the apparatus controlled accordingly. In embodiments where the first and second time points (or the time interval between them) are predetermined by the electrical design (analog circuit design) of the apparatus, using the apparatus of the eleventh or thirteenth aspect or performing the method according to the twelfth aspect also results in the corresponding time interval between the first and second time points.

[0187] In a fourteenth aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a first inductor for generating a first magnetic field for application to body tissue; a second inductor for generating a second magnetic field; a connection circuit between the power storage device and the first and second inductors, the connection circuit comprising a first branch between the power storage device and the first inductor and a second branch between the power storage device and the second inductor; a first switching device forming part of the first branch, the first switching device configured to electrically connect the power storage device to the first inductor and to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor, thereby causing the first inductor to generate a first magnetic field, the current flowing through the first branch representing a first current direction of current flow with respect to the power storage device; and a second switching device forming part of the second branch, the second switching device configured to electrically connect the power storage device to the second inductor and to allow a current caused by electrical energy stored using the power storage device to flow through the second branch and through the second inductor, thereby causing the second inductor to generate a second magnetic field, the current flowing through the second branch representing a second current direction of current flow relative to the power storage device, the second current direction of current flow being opposite to the first current direction of current flow.

[0188] In some embodiments, the apparatus according to the fourteenth aspect can be fabricated similarly to the circuit described with respect to FIG. 1, except that: a) the provision of a second inductor; b) providing a first branch between the power storage device and the first inductor, and providing a second branch between the power storage device and the second inductor; c) providing first and second switching devices; and d) With respect to the energy storage device, the second current direction of current flow through the second branch being opposite to the first current direction of current flow through the first branch results in significant differences not only in the structure of the device, but also in the operation of the device, as will be explained below.

[0189] The explanations given above with respect to the first, fifth, eighth and eleventh aspects also apply to the fourteenth aspect, in particular the storage device together with the first inductor and the connecting circuit can be considered (similar to) a resonant circuit (or LC circuit); the storage device, together with the second inductor and the connecting circuit, can be considered (similar to) a resonant circuit (or LC circuit); the frequency ω0 of the resonant circuit is (approximately) determined by the values ​​of the (applicable) inductance L and capacitance C of the circuit, according to ω0=1 / (√(LC)), whereby the applicable inductance includes in particular the inductance of the first or second inductor; - the type of inductor used as the first inductor and / or the second inductor, - types of switching devices (for use as first and second switching devices) and methods of operating them, - the phrases "electrically connected" and "electrically connected"; This applies in respect of:

[0190] The circuit according to the fourteenth aspect allows the first and second inductors to be used in various ways, in particular substantially independently of each other or in cooperation. Nevertheless, it is in principle also possible to operate the circuit according to the fourteenth aspect with only one storage device, such as a capacitor, but it is equally possible to provide a capacitor arrangement comprising several capacitors as storage devices. In any case, it is not necessary to provide a separate storage device for each inductor.

[0191] The first inductor may, for example, be housed within a first casing that can be moved by an operator and placed on a human or animal body part.

[0192] In one embodiment, the first and second inductors are not connected in series, i.e., in particular, current through the first inductor does not flow through the second inductor and vice versa, and therefore the first and second branches may be considered to be substantially independent of each other, except that they are both connected to the power storage device.

[0193] In one embodiment, the first switching device is configured to allow current to flow about the power storage device only in a first current direction; The second switching device is configured to allow current to flow about the power storage device only in a second current direction. Suitable switching devices include, but are not limited to, thyristors, gate turn-off thyristors (GTO thyristors), IGBTs, and FETs.

[0194] In one embodiment, the second inductor is configured to also apply a second magnetic field to the body tissue. For example, the second inductor can be housed within a first casing that can be moved by an operator and placed in a human or animal body part.

[0195] According to one variant, the second magnetic field generated by the second inductor is not necessarily intended for application to body tissue. Of course, a magnetic field can in principle have an infinite extent, so that body tissue subjected to the magnetic field generated by the first inductor will also be subjected to the second magnetic field generated by the second inductor. In one such variant, however, the effect of this can be kept small, for example, by locating the second inductor at a suitable distance from the first inductor (and thus from any body tissue to which the first magnetic field generated by the first inductor should be applied). The second inductor can be housed, for example, in a metallic housing, in particular a metallic housing that also houses other parts of the circuit of the fourteenth aspect, such as the power storage device.

[0196] In one embodiment, the first inductor comprises at least a first set of turns, preferably at least a first set of generally circular, hexagonal, or rectangular turns; some of the turns of the first set of turns are preferably arranged such that when a current flows through the first inductor, each turn produces a contribution towards the first magnetic field, the contributions produced by each turn being superimposed in a positive manner; the first inductor is disposed within a first casing connected to a first conduit through which at least a first cable passes for supplying power to the first set of windings; The second inductor is not disposed within the first casing.

[0197] According to this embodiment, the first inductor may be arranged in a casing, for example made of a plastic material, which may be separate from and separately movable with respect to a unit, such as a housing or cabinet, which contains the power storage device, the first and second switching devices, and at least a part of the first and second branches of the connection circuit. The casing containing the first inductor may be connected to the cabinet by a conduit tube containing a cable for supplying power to the first inductor. An arrangement in which the first inductor and the casing containing the first inductor are connected to other parts of the device by means of a conduit tube such that the first inductor can be relatively moved with respect to such other parts may advantageously be used to bring the first inductor close to body tissue without moving these other parts (e.g. the cabinet containing these other parts and which may be significantly larger and heavier than the first inductor and the casing containing the first inductor).

[0198] In one embodiment, the second inductor comprises at least a second set of turns, preferably at least a second set of generally circular, hexagonal, or rectangular turns; some of the turns of the second set of turns are preferably arranged such that when a current flows through the second inductor, each turn produces a contribution towards the second magnetic field, the contributions produced by each turn being superimposed in a positive manner; the second inductor is disposed within a second casing connected to a second conduit through which at least a second cable passes for supplying power to the second set of windings; The first inductor is not disposed within the second casing.

[0199] According to this embodiment, the second inductor may be arranged in a casing, for example made of a plastic material, which may be separate from and separately movable with respect to a unit, such as a housing or cabinet, which contains the power storage device, the first and second switching devices, and at least a part of the first and second branches of the connection circuit. The casing containing the second inductor may be connected to the cabinet by a conduit tube containing a cable for supplying power to the second inductor. An arrangement in which the second inductor and the casing containing the second inductor are connected to other parts of the device by means of a conduit tube such that the second inductor can be relatively moved with respect to such other parts may advantageously be used to bring the second inductor close to body tissue without moving these other parts (e.g. the cabinet containing these other parts and which may be significantly larger and heavier than the second inductor and the casing containing the second inductor).

[0200] Alternatively, the first and second inductors may be contained within the same housing.

[0201] In one embodiment, the first inductor is wound on a first core and the second inductor is wound on a second core different from the first core, such that the first inductor and the second inductor are not substantially magnetically coupled, at least not via a core common to both inductors.

[0202] In one embodiment, the first inductor and the second inductor are movable independently of one another, particularly while remaining connected to the remainder of the device, particularly during energization or use, although the connection to the remainder of the device will of course impose limitations as to the area or radius around the remainder of the device within which the first and second inductors can move.

[0203] In one embodiment, the first inductance of the first inductor and / or the second inductance of the second inductor are either discretely variable and substantially continuously variable, which allows the resonant frequency of the resonant circuit to be varied discretely or substantially continuously.

[0204] In one embodiment, the power storage device comprises a pulse capacitor that can be charged by a charging circuit that can form part of the apparatus or can be provided as a separate device for connection to the apparatus of the fourteenth aspect. The charging circuit can in particular comprise a voltage source and a switch for selectively connecting the voltage source to the capacitor.

[0205] In a fifteenth aspect of the present disclosure, a method for generating a magnetic field is provided, the method comprising: Providing an apparatus according to a fourteenth aspect; Storing electrical energy in an electrical storage device; switching a first switching device to electrically connect the power storage device to the first inductor, thereby allowing a current caused by electrical energy stored with the power storage device to flow through the first inductor through the first branch in a first current direction of current flow about the power storage device, thereby causing the first inductor to generate a first magnetic field; switching a second switching device to electrically connect the storage device to the second inductor, thereby allowing a current caused by the electrical energy stored using the storage device to flow through the second branch and through the second inductor in a second current direction of current flow about the storage device, thereby causing the second inductor to generate a second magnetic field.

[0206] The embodiments described with respect to the fourteenth aspect apply equally to the fifteenth aspect and vice versa.

[0207] In one embodiment, the device is operated in a pulsed manner, where current through the first branch represents a first half-pulse and current through the second branch represents a second half-pulse, the first half-pulse and the second half-pulse together forming one pulse.

[0208] The device according to this embodiment is operated so that at least one (full) pulse is performed, but each branch and each of the first and second inductors is used to perform only one half-pulse.

[0209] In one embodiment, switching the second switching device includes switching the second switching device after a delay after the end of the first half-pulse. This delay may be particularly variable or particularly selectable by the user. Thus, the two half-pulses can be performed substantially independently of each other. The delay may be set by the user via a user interface, for example a dial or touch screen of the device. The device may include analog circuitry and / or a microcontroller to control the second switching device according to the selected delay.

[0210] In one embodiment, the first half-pulse has a first duration and the delay is longer than the first duration. According to this embodiment, the second half-pulse is therefore not performed immediately after the end of the first half-pulse or very shortly after the first half-pulse. Alternatively, the delay can be selected to be shorter than the first duration.

[0211] In one embodiment, the method includes bringing a first inductor close to the body tissue or bringing the body tissue close to a first inductor such that a first magnetic field is present in the body tissue, which may be used in particular for therapeutic purposes, but may also be used for non-therapeutic purposes.

[0212] In one embodiment, the method further includes varying the first magnetic field in the body tissue to generate a voltage in the body tissue or to cause a movement of charge in the body tissue. When the magnetic field in the body tissue changes with the current through the first inductor, a voltage is generated (or a movement of charge is caused) in the body tissue passing through the magnetic field.

[0213] In one embodiment, the voltage (or charge transfer) generated in the body tissue is sufficient to induce a neural or cellular physiological response, particularly a muscular response, in the body tissue; Preferably, the voltage or charge transfer generated is sufficient to cause a therapeutic effect.

[0214] Various effects can be achieved in a targeted manner using the device of the fourteenth aspect or the method of the fifteenth aspect. In particular, when only the first inductor is brought close to the body tissue (and the second inductor is not brought close to the body tissue), the resulting voltage or charge movement in the body tissue is oriented in only one direction. When the device is operated in a pulsed manner by repeatedly applying pulses, this results in an accumulation of this effect.

[0215] In one embodiment, the method further comprises bringing a second inductor close to the body tissue or bringing the body tissue close to a second inductor such that a second magnetic field is present within said body tissue.

[0216] In this context, the second inductor may be brought close to the same body part as the first inductor, or alternatively to a different body part. Furthermore, the generated voltage or charge movement in the body tissue caused by the second inductor may be oriented in the same direction as the generated voltage or charge movement in the body tissue caused by the first inductor, or in a different direction, in particular in the opposite direction. If the voltage or charge movement in the body tissue caused by the first and second inductors, respectively, is oriented in the opposite direction, this is expected to reduce the net charge displacement (when the effects of the first and second inductors are considered together). If oriented in the same direction, this is expected to increase the net charge displacement (when the effects of the first and second inductors are considered together).

[0217] In one example, a body part, such as a finger, hand, arm, etc., is placed between two inductors, and depending on the orientation of the inductors relative to each other, the voltage or charge movement in the body tissue caused by the first and second inductors, respectively, can be oriented in the same direction, opposite directions, or neither the same nor opposite directions.

[0218] In a sixteenth aspect of the present disclosure, there is provided an apparatus for use with a first inductor and a second inductor, the first inductor for generating a magnetic field for application to body tissue, the apparatus comprising: a storage device for storing electrical energy; a first terminal for connection to a first inductor for generating a first magnetic field for application to body tissue; a second terminal for connection to a second inductor for generating a second magnetic field; a connection circuit between the power storage device and the first and second terminals, the connection circuit including at least a first branch connected to the first terminal and a second branch connected to the second terminal; a first switching device forming part of a first branch, the first switching device electrically connecting the power storage device to a first terminal and configured to allow a current caused by electrical energy stored with the power storage device to flow through the first branch and through the first inductor via the first terminal when the first inductor is connected to the apparatus via the first terminal, thereby causing the first inductor to generate a first magnetic field, the current flowing through the first branch representing a first current direction of current flow with respect to the power storage device; and a second switching device forming part of the second branch, the second switching device electrically connecting the power storage device to a second terminal and configured to allow a current caused by electrical energy stored using the power storage device to flow through the second branch and through the second inductor via the second terminal when the second inductor is connected to the apparatus via the second terminal, thereby causing the second inductor to generate a second magnetic field, the current flowing through the second branch representing a second current direction of current flow with respect to the power storage device, the second current direction of current flow being opposite to the first current direction of current flow.

[0219] The device of the 16th embodiment is similar to the device of the 14th embodiment. However, in contrast to the 14th embodiment, the first and second inductors mentioned in relation to the 16th embodiment do not form part of the device of the 16th embodiment. Instead, the device of the 16th embodiment has first and second terminals (such as electrical sockets or similar) for connecting to the first and second inductors, respectively. Thus, multiple (different) inductors, e.g., inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the 16th embodiment and used as the first and second inductors.

[0220] In a seventeenth aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a capacitor arrangement comprising at least one capacitor for storing electrical energy; a charging circuit for charging the at least one capacitor; an inductor for generating a magnetic field for application to body tissue; a connection circuit between the capacitor arrangement and the inductor, the connection circuit having at least a first branch and a second branch; a first switching device forming part of the first branch, the first switching device configured to electrically connect the capacitor arrangement to the inductor and to allow a current caused by electrical energy stored using the capacitor arrangement to flow through the first branch and through the inductor, thereby causing the inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the capacitor arrangement and the inductor; an electric component or assembly, preferably an electronic component or assembly, forming part of the second branch, the electric component or assembly configured to electrically connect the capacitor arrangement to the inductor and to allow a current caused by electrical energy stored with the capacitor arrangement to flow through the second branch and through the inductor, thereby causing the inductor to generate a magnetic field, the current flowing through the second branch representing a second current direction of current flow between the capacitor arrangement and the inductor, the second current direction being opposite to the first current direction, The charging circuit includes a first voltage source; a) the charging circuit comprises a second voltage source, the first voltage source being arranged to charge at least one capacitor having a first polarity and the second voltage source being arranged to charge at least one capacitor having a second polarity opposite the first polarity; b) the charging circuit comprises a switching arrangement, in particular a switching arrangement including an H-bridge, the switching arrangement being arranged to electrically connect a first voltage source to the capacitor arrangement in a first manner so as to charge the at least one capacitor with a first polarity, and the switching arrangement being arranged to electrically connect the first voltage source to the capacitor arrangement in a second manner so as to charge the at least one capacitor with a second polarity opposite to the first polarity; c) at least one of the following applies: the charging circuit includes an auxiliary capacitor, the first voltage source is configured to charge the at least one capacitor with a first polarity, and the auxiliary capacitor is configured to charge the at least one capacitor with a second polarity opposite to the first polarity.

[0221] In some embodiments, a device according to the seventeenth aspect can be fabricated similarly to the circuit described with respect to Figure 1. However, providing a charging circuit and fabricating the charging circuit such that at least one capacitor can be charged with a first polarity and a second polarity opposite the first polarity makes a significant difference not only in the fabrication of the device, but also in the operation of the device, as described below.

[0222] The explanations given above with respect to the first, fifth, eighth, eleventh and fourteenth aspects also apply equally to the seventeenth aspect, in particular - at least one capacitor (or a capacitor arrangement including at least one capacitor) of the seventeenth aspect, which is a form of an electric storage device (first, fifth and fourteenth aspects), together with an inductor and a connecting circuit, can be regarded as (similar to) a resonant circuit (or an LC circuit); the frequency ω0 of the resonant circuit is (approximately) determined by the values ​​of the (applicable) inductance L and capacitance C of the circuit, according to ω0=1 / (√(LC)), whereby the applicable inductance includes in particular the inductance of the inductor (and of any additional inductors, if provided); - type of inductor for use as inductor, - types of switching devices and methods of operating them; - the phrases "electrically connected" and "electrically connected"; - types of components that can be used as electrical (or electronic) components or as part of electrical (or electronic) component assemblies in the second branch This applies with respect to:

[0223] Common to all three options a), b) and c) of the device according to the seventeenth aspect is at least the fact that the charging circuit is capable of charging at least one capacitor with a first polarity and with a second polarity opposite to the first polarity, whereby options a), b) and c) provide three different implementations for this. However, embodiments in which at least two of these three options may be used in combination are also possible, and in particular option c) may be used in combination with either option a) or b), as will be explained below.

[0224] In the case of option b), the first voltage source and the switching arrangement may be provided as separate units. However, alternative b) is intended to be understood to also encompass implementations in which a voltage source with reversible polarity is used as the first voltage source, in particular a voltage source with an integrated switching arrangement, e.g. a voltage source with an (integrated) H-bridge.

[0225] In one embodiment, the apparatus is arranged to operate in a pulsed manner resulting in at least one current pulse in the inductor having a first half-pulse and a second half-pulse, the charging circuitry is arranged to charge the at least one capacitor with a first polarity before or at the beginning of the first half-pulse, and the charging circuitry is arranged to charge the at least one capacitor with a second polarity before or at the beginning of the second half-pulse.

[0226] Although the energy stored in the magnetic field is transferred back to the at least one capacitor during the second half of the first half-pulse (i.e. the second quarter pulse), thereby charging the capacitor with a second polarity, the inventors have realized that some energy losses tend to occur in the device, such that the energy stored in the at least one capacitor just before the beginning of the first half-pulse is not fully transferred to the magnetic field during the first quarter-pulse, and the energy stored in the magnetic field is not fully transferred back again to the at least one capacitor during the second quarter-pulse. In other words, if the recharging of the capacitor by the charging circuit does not take place before the second half-pulse or at the beginning of the second half-pulse, the energy stored in the at least one capacitor at the beginning of the second half-pulse will be less than the energy stored in the at least one capacitor at the beginning of the first quarter-pulse. The present embodiment allows this energy loss to be at least partially compensated, or even fully compensated.

[0227] In one embodiment, the charging circuit is arranged to charge the at least one capacitor with a first polarity to a first voltage and the charging circuit is arranged to charge the at least one capacitor with a second polarity to a second voltage, the absolute values ​​of the first and second voltages differing from each other by at most 10%, in particular at most 5%, in particular at most 3%, in particular at most 2%, in particular at most 1%. In this way, the voltage of the at least one capacitor at the beginning of the second half-pulse can be substantially the same as at the beginning of the first half-pulse - except for the opposite polarity.

[0228] In one embodiment, when an inductor is brought close to a body tissue or when the body tissue is brought close to a second inductor, a first magnetic field is present in said body tissue during a first half-pulse, resulting in a first displacement of charge in the body tissue, and a second magnetic field is present in said body tissue during a second half-pulse, resulting in a second displacement of charge in the body tissue, the first displacement of charge and the second displacement of charge being oriented in substantially opposite directions; The charging circuit is configured to charge the at least one capacitor with a first polarity until a first voltage is reached, and the charging circuit is configured to charge the at least one capacitor with a second polarity until a second voltage is reached, the absolute values ​​of the first and second voltages being such that the absolute values ​​of the first displacement of charge and the second displacement of charge differ from each other by at most 10%, in particular at most 5%, in particular at most 3%, in particular at most 2%, in particular at most 1%, and in particular the net charge displacement in the body tissue resulting from the first and second half-pulses is substantially zero.

[0229] Ensuring that the net charge displacement within bodily tissue is kept low, in particular (substantially) zero, may have beneficial effects on the bodily tissue (or the person or animal receiving the treatment) when compared with treatments that result in the net charge displacement within the bodily tissue not being kept low.

[0230] Ensuring that the net charge displacement in the body tissue is kept low, in particular (substantially) zero, is sometimes, but not necessarily, equivalent to charging at least one capacitor to the same voltage at the beginning of the first half-pulse and at the beginning of the second half-pulse. In particular, many parameters affect the duration, magnitude and / or shape of the first and second half-pulses. Such parameters include the electrical properties of the first and second branches. The present invention in particular enables such parameters to be taken into account when charging at least one capacitor before or at the beginning of the first and second half-pulses in order to keep the net charge displacement in the body tissue low, in particular (substantially) zero.

[0231] In the context of this embodiment, it is noted that the charge displacement in the body tissue will not usually take the form of a (substantially) linear displacement, but will typically take the form of a (substantially) ring (or will typically occur in an approximately ring-shaped, in particular doughnut-shaped, volume), in particular will follow an approximately circular path. The meaning of the expression "the first displacement of charge and the second displacement of charge are oriented in substantially opposite directions" is therefore intended to encompass the case where the direction of such ring-shaped or doughnut-shaped currents is reversed when comparing the first half-pulse and the second half-pulse.

[0232] In one embodiment, the device further comprises at least one controller or analog circuitry arranged to control the selective charging of the at least one capacitor with the first and second polarities. The at least one controller may, in particular, include a microcontroller. In particular, the at least one controller may not only control the charging of the at least one capacitor but also control the first switching device, in particular, cause the first switching device to switch from a non-conducting state to a conducting state and / or vice versa. The at least one controller may also control the charging of the at least one capacitor or the control of the first switching device, in particular, depending on the timing of the switching of the first switching device from a non-conducting state to a conducting state and / or vice versa, to ensure that the charging of the at least one capacitor is timed appropriately.

[0233] In one embodiment, the electrical component or electrical component assembly comprises a second switching device for electrically connecting the capacitor arrangement to the inductor in a selective manner, in particular under the control of at least one controller or analog circuit; or The electrical component or electrical component assembly is arranged to carry current primarily in a forward direction, the forward direction corresponding to a second current direction of current flow between the capacitor arrangement and the inductor.

[0234] According to a first of these options, the second switching device may comprise the components described for the first switching device, so that in certain embodiments the first and second switching devices do not have to be of the same type. According to a second of these options, various components may be used as electrical (or electronic) components or as part of an electrical (or electronic) component assembly in the second branch. This includes diodes, in particular diodes with pn junctions or metal-semiconductor junctions (Schottky contacts). More generally, this includes components with a similar function to diodes, including rectifiers such as electrolytic rectifiers, mercury rectifiers, plate rectifiers (metal rectifiers, in particular selenium rectifiers) and vacuum tube rectifiers (vacuum tube diodes). These components may be considered as passive rectifiers, i.e. rectifiers that do not require additional circuitry to affect the behavior of the rectifier. In any case, according to both options, analog circuitry may be used instead of or in addition to the controller to control the charging of the first switching device (and / or the second switching device, if provided) and / or the at least one capacitor.

[0235] In an eighteenth aspect of the present disclosure, a method of generating a magnetic field is provided, the method comprising, in a specifically defined order: Providing an apparatus according to a seventeenth aspect; charging at least one capacitor with a first polarity; switching a first switching device to electrically connect the capacitor arrangement to the inductor, thereby allowing a current caused by the electrical energy stored with the capacitor arrangement to flow through the first branch and through the first inductor, thereby causing the first inductor to generate a magnetic field; charging at least one capacitor with a second polarity; and allowing current to flow through the electrical component or electrical component assembly through a second branch between the capacitor arrangement and the inductor.

[0236] The embodiments described with respect to the seventeenth aspect equally apply to the eighteenth aspect and vice versa.

[0237] In one embodiment, the method further includes operating the device in a pulsed manner, where the current through the first branch represents a first half-pulse and the current through the second branch represents a second half-pulse, the first half-pulse and the second half-pulse together forming a pulse.

[0238] In one embodiment, allowing current to flow between the at least one capacitor and the inductor through said electrical component or electrical component assembly and through the second branch includes allowing current to flow through the second branch after a delay after the end of the first half-pulse. This delay may in particular be variable or selectable by the user or the manufacturer. Thus, the two half-pulses can be performed substantially independently of each other. The delay may be set by the user via a user interface, for example a dial or a touch screen of the device. The device may comprise an analog circuit and / or a microcontroller to control the second switching device according to the selected delay. Introducing a delay between the end of the first half-pulse and the beginning of the second half-pulse may allow a charging circuit to charge the at least one capacitor during this delay.

[0239] In one embodiment, the method comprises: charging at least one capacitor with a first polarity; - switching a first switching device to electrically connect the capacitor arrangement to the inductor; charging the at least one capacitor with a second polarity; and - allowing current to flow through the second branch using at least one controller or analog circuitry.

[0240] In one embodiment, when at least c) is applied, the method further comprises charging the auxiliary capacitor before the end of the first half-pulse, in particular before the first half-pulse and / or during the first half-pulse; After the first half-pulse, causing an auxiliary capacitor to charge the at least one capacitor.

[0241] The use of an auxiliary capacitor to charge the at least one capacitor may have particular advantages. It may be desirable to keep the delay between the end of the first half-pulse and the beginning of the second half-pulse as short as possible while keeping the net charge displacement in the body tissue low - for this purpose, some embodiments of the present disclosure contemplate charging the at least one capacitor with the second polarity before or at the beginning of the second half-pulse, in particular to compensate for energy losses in the circuit. If the at least one capacitor is charged with the second polarity directly from a voltage source, this voltage source may need to have a relatively high output power to reduce the time it takes to charge the at least one capacitor. On the other hand, the auxiliary capacitor may be able to charge the at least one capacitor very quickly. Thus, the auxiliary capacitor may be charged for a relatively long period of time before and / or during the first half-pulse, and then the at least one capacitor may be charged during a relatively short period of time between the first and second half-pulses.

[0242] In one embodiment, charging the auxiliary capacitor includes charging the auxiliary capacitor with a second voltage source, in particular the second voltage source having a smaller output power than the first voltage source.

[0243] As explained above, the second voltage source does not need to have a particularly high output power because the auxiliary capacitor can be charged over a relatively long period of time. Nevertheless, as explained above, charging of the at least one capacitor by the auxiliary capacitor can occur in a relatively short period of time.

[0244] In one variant, the first voltage source may be used in combination with a switching arrangement - such as that described above under option b) - to charge the auxiliary capacitor, in which case no second voltage source is required.

[0245] In a nineteenth aspect of the present disclosure, there is provided an apparatus for use with an inductor to generate a magnetic field for application to body tissue, the apparatus comprising: a capacitor arrangement comprising at least one capacitor for storing electrical energy; a charging circuit for charging the at least one capacitor; a terminal for connecting to an inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the capacitor arrangement and the terminal, the connection circuit having at least a first branch and a second branch; a switching device forming part of a first branch, the switching device electrically connecting the capacitor arrangement to a terminal and configured to allow a current caused by electrical energy stored using the capacitor arrangement to flow through the first branch and through the inductor via the terminal when the inductor is connected to the apparatus via the terminal, thereby causing the inductor to generate a magnetic field, the current flowing through the first branch representing a first current direction of current flow between the capacitor arrangement and the terminal; an electrical component or assembly, preferably an electronic component or assembly, forming part of a second branch, the electrical component or assembly configured to electrically connect a capacitor arrangement to the terminals and to allow a current caused by electrical energy stored using the capacitor arrangement to flow through the second branch and through the inductor via the terminals when the inductor is connected to a device via the terminals, thereby causing the inductor to generate a magnetic field, the current flowing through the second branch representing a second current direction of current flow between the capacitor arrangement and the terminals, the second current direction of current flow being opposite to the first current direction of current flow, The charging circuit includes a first voltage source; a) the charging circuit comprises a second voltage source, the first voltage source being arranged to charge the at least one capacitor with a first polarity and the second voltage source being arranged to charge the at least one capacitor with a second polarity opposite the first polarity; b) the charging circuit comprises a switching arrangement, in particular a switching arrangement including an H-bridge, the switching arrangement being arranged to electrically connect a first voltage source to the capacitor arrangement in a first manner so as to charge the at least one capacitor with a first polarity, and the switching arrangement being arranged to electrically connect the first voltage source to the capacitor arrangement in a second manner so as to charge the at least one capacitor with a second polarity opposite to the first polarity; c) at least one of the following applies: the charging circuit includes an auxiliary capacitor, the first voltage source is configured to charge the at least one capacitor with a first polarity, and the auxiliary capacitor is configured to charge the at least one capacitor with a second polarity opposite to the first polarity.

[0246] The device of the 19th embodiment is similar to the device of the 17th embodiment. However, in contrast to the 17th embodiment, the inductor mentioned in relation to the 19th embodiment does not form part of the device of the 19th embodiment. Instead, the device of the 19th embodiment has a terminal (such as an electrical socket or similar) for connecting to the inductor. Thus, multiple (different) inductors, e.g., inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the 19th embodiment and used as the inductor of the 19th embodiment.

[0247] In a twentieth aspect of the present disclosure, there is provided an apparatus for generating a magnetic field for application to body tissue, the apparatus comprising: a first series combination of a first switching device and a second switching device, the first switching device being electrically connected to the second switching device at a first node; a second series combination of a third switching device and a fourth switching device, the third switching device being electrically connected to the fourth switching device at a second node; a DC power arrangement including at least one DC power source for supplying electrical energy; an inductor for generating a magnetic field for application to body tissue; the first series combination is electrically connected in parallel with the second series combination at a third node and a fourth node, the first switching device and the third switching device are electrically connected at the third node, and the second switching device and the fourth switching device are electrically connected at the fourth node; a first terminal of the inductor electrically connected to the third node, and a second terminal of the inductor electrically connected to the fourth node; the DC power arrangement is electrically connected between the first connection point and the second connection point; the first and fourth switching devices are configured to be switched from a substantially non-conductive state to a conductive state, such that from a first time point, the first and fourth switching devices are both in a conductive state and the second and third switching devices are both in a substantially non-conductive state; the first and fourth switching devices are configured to be switched from a conductive state to a substantially non-conductive state, such that from a second time point after the first time point, the first and fourth switching devices are both in a substantially non-conductive state; the second and third switching devices are configured to be switched from a substantially non-conductive state to a conductive state, such that from the second time point or a third time point after the second time point, the second and third switching devices are both in a conductive state and the first and fourth switching devices are both in a substantially non-conductive state; between the first and second times, current caused by electrical energy supplied by the DC power arrangement is arranged to flow through the first and fourth switching devices and through the inductor in a first current direction of current flow relative to the inductor, thereby causing the inductor to generate a magnetic field; After a third time point, a current caused by the electrical energy supplied by the DC power supply arrangement is arranged to flow through the second switching device and the third switching device and through the inductor in a second current direction of current flow relative to the inductor opposite to the first current direction of current flow, thereby causing the inductor to generate a magnetic field.

[0248] At least some of the explanations provided above with respect to the first, fifth, eighth, eleventh, fourteenth and seventeenth aspects also apply to the twentieth aspect as well, in particular - type of inductor for use as inductor, - types of switching devices and methods of operating them; - the phrases "electrically connected" and "electrically connected"; This applies in respect of:

[0249] Although an embodiment of the twentieth aspect may not be considered to include a resonant circuit (or a circuit portion similar to a resonant circuit), it is nevertheless possible to use the first to fourth switching devices of the twentieth aspect to generate current pulses, and in particular current pulses having opposite polarity, to cause the inductor to generate a changing magnetic field, in particular a pulsed magnetic field.

[0250] Although the twentieth aspect defines first to third time points, it is also possible to optionally switch the second and third switching devices from a conducting state to a substantially non-conducting state such that from a fourth time point after the third time point, the second and third switching devices are both in a substantially non-conducting state. Assuming that the first and fourth switching devices are also (still) in a substantially non-conducting state, the apparatus returns substantially to an initial state, i.e. a state prior to the first time point.

[0251] In one embodiment, the apparatus further comprises at least one controller, in particular a microcontroller, for controlling one or more of the first, second, third and fourth switching devices to switch between a substantially non-conducting state and a conducting state.

[0252] Embodiments are possible in which one controller controls several of the switching devices, in particular all of the switching devices. Alternatively, several controllers may be provided, each controller controlling a subset of the first switching devices, in particular on a one-to-one basis.

[0253] In one embodiment, at least one controller includes an interface, such as a dial or touch screen, through which a user or manufacturer can specify or select any one or more of the first through third (and, if applicable, fourth) time points. Such interfaces have been described with respect to other aspects of this disclosure, and reference should be made to those portions herein.

[0254] In one embodiment, the apparatus further comprises analog circuitry for controlling one or more of the first, second, third, and fourth switching devices to switch between a substantially non-conducting state and a conducting state.

[0255] Regardless of whether a controller (such as a microcontroller) or an analog circuit is used to control the first to fourth switching devices, the control can be such that any one or more of the first to fourth switching devices are switched between a substantially non-conducting state and a conducting state at a predetermined or selected time point. Alternatively or in addition, parameters prevailing at a certain point in the circuit (such as the current through an inductor) or between certain points in the circuit (such as the voltage between two points in the circuit) can be taken into account by the (micro)controller or analog circuit, which for this purpose can receive suitable inputs from several parts of the circuit - in effect a measurement of a current or voltage, or a measurement of another parameter. The circuit can, for example, include feedback loops for making inputs from several parts of the circuit to the controller or analog circuit, so that these inputs can affect the behavior of the controller or analog circuit, or the controller or analog circuit can adapt its behavior based on such inputs / measurements. This can be applied to the control of any other switching devices disclosed herein as well.

[0256] In one embodiment, the apparatus further comprises at least one additional electrical circuit element, which is configured to switch from a substantially non-conductive state to a conductive state (or more generally, to change its conductivity) when the voltage between some points within the apparatus is selected or exceeds a predetermined voltage value, particularly when the voltage across any one or more of the first to fourth switching devices and / or the voltage across the inductor is selected or exceeds a predetermined voltage value.

[0257] At least one additional electrical circuit element can help prevent damage or destruction of other elements in the circuit, such as the first to fourth switching elements. As an example, by using protection against voltages that would cause damage or destruction to the circuit element to be protected, preferably the following criteria are met with respect to the voltage (absolute value) involved. The circuit design is such that in normal use, the circuit element to be protected can be subjected to a voltage up to U1. The additional electrical circuit element is rated at a voltage U2, i.e., it is configured to switch from a substantially non-conductive state to a conductive state at the voltage U2. The circuit element to be protected is damaged or destroyed at a voltage U3 or higher, where U1 < U2 < U3. By complying with this regulation, it can be ensured that the additional electrical circuit element is not already in a conductive state at the voltages encountered during normal operation of the circuit. At the same time, this can ensure that the circuit element to be protected is not damaged or destroyed.

[0258] In one embodiment, the at least one additional electrical circuit element is one or more passive electrical circuit elements, particularly - a spark gap, - a transient voltage suppression diode, - a Zener diode, - a Shockley diode, or - a triode for alternating current (TRIAC), or - a thyristor, Includes one or more of:

[0259] If the at least one additional electric circuit element comprises a passive electric circuit element, it simply "reacts" to the conditions prevailing in the circuit, e.g., a voltage applied to the terminals of the passive electric circuit element. If the at least one additional electric circuit element comprises circuit elements not normally considered to be passive electric circuit elements (e.g., TRIACs and thyristors), it must be actively switched. This switching may again be triggered by conditions prevailing in the circuit, e.g., a voltage between two particular points in the circuit.

[0260] In one embodiment, at least one additional electrical circuit element is connected in parallel with one or more of the first through fourth switching devices and / or the inductor.

[0261] This can serve to provide particularly effective protection for the switching devices and / or inductors. For example, if the voltage applied to one of the switching devices becomes high beyond a level that could cause damage to or destroy the switching device, the additional electrical circuit element will see substantially the same voltage (assuming there is no significant voltage drop across the other circuit elements). The additional electrical circuit element will then become conductive, which can significantly reduce the voltage across the switching device.

[0262] In one embodiment, the device comprises one or more inductors, in particular one or more additional inductors connected in parallel to said inductor or in series to said inductor.

[0263] The one or more additional inductors may or may not be intended to generate a magnetic field for application to body tissue. Furthermore, the one or more additional inductors may or may not be housed within a casing or similar in which the first mentioned inductor is housed. In particular, the one or more additional inductors may or may not be movable independently of the first mentioned inductor.

[0264] In one embodiment, the at least one DC power source comprises: -Battery, - solar panels or modules, - fuel cell Includes at least one of the following:

[0265] Several DC power sources may be used, either in combination of the same type or different types. Furthermore, when multiple DC power sources are used, they may be connected in parallel or in series, depending on the intended application. Ideally, the DC power sources have low internal resistance. Furthermore, ideally, the DC power sources are capable of supporting a relatively large current.

[0266] In a twenty-first aspect of the present disclosure, there is provided a method of generating a magnetic field, the method comprising: Providing an apparatus according to a twentieth aspect; switching the first and fourth switching devices from a substantially non-conductive state to a conductive state at a first time while the second and third switching devices are both in a substantially non-conductive state; switching the first and fourth switching devices from a conductive state to a substantially non-conductive state at a second time point after the first time point; switching the second and third switching devices from the substantially non-conductive state to the conductive state at a third time after the second time while the first and fourth switching devices are both in a substantially non-conductive state.

[0267] Optionally, the method further comprises switching the second and third switching devices from a conductive state to a substantially non-conductive state at a fourth time point after the third time point.

[0268] In a twenty-second aspect of the present disclosure, there is provided an apparatus for use with an inductor to generate a magnetic field for application to body tissue, the apparatus comprising: a first series combination of a first switching device and a second switching device, the first switching device being electrically connected to the second switching device at a first node; a second series combination of a third switching device and a fourth switching device, the third switching device being electrically connected to the fourth switching device at a second node; a DC power arrangement including at least one DC power source for supplying electrical energy; a first terminal and a second terminal for connection to an inductor for generating a magnetic field to be applied to body tissue; the first series combination is electrically connected in parallel with the second series combination at a third node and a fourth node, the first switching device and the third switching device are electrically connected at the third node, and the second switching device and the fourth switching device are electrically connected at the fourth node; The first terminal is electrically connected to the third connection point, and the second terminal is electrically connected to the fourth connection point; the DC power arrangement is electrically connected between the first connection point and the second connection point; the first and fourth switching devices are configured to be switched from a substantially non-conductive state to a conductive state, such that from a first time point, the first and fourth switching devices are both in a conductive state and the second and third switching devices are both in a substantially non-conductive state; the first and fourth switching devices are configured to be switched from a conductive state to a substantially non-conductive state, such that from a second time point after the first time point, the first and fourth switching devices are both in a substantially non-conductive state; the second and third switching devices are configured to be switched from a substantially non-conductive state to a conductive state, such that from the second time point or a third time point after the second time point, the second and third switching devices are both in a conductive state and the first and fourth switching devices are both in a substantially non-conductive state; Between a first time point and a second time point, a current caused by the electrical energy supplied by the DC power arrangement is arranged to flow through the inductor via the first and second terminals and through the first and fourth switching devices when the inductor is connected to the apparatus via the first and second terminals, thereby causing the inductor to generate a magnetic field, the current through the first and fourth switching devices representing a first current direction of current flow relative to the inductor; After a third time point, a current caused by the electrical energy supplied by the DC power arrangement is arranged to flow through the inductor via the first and second terminals and through the second and third switching devices when the inductor is connected to the apparatus via the first and second terminals, thereby causing the inductor to generate a magnetic field, and the current through the second and third switching devices represents a second current direction of current flow relative to the inductor opposite to the first current direction.

[0269] The device of the 22nd embodiment is similar to the device of the 20th embodiment. However, in contrast to the 20th embodiment, the inductor mentioned in relation to the 20th embodiment does not form part of the device of the 22nd embodiment. Instead, the device of the 22nd embodiment has first and second terminals (such as an electrical socket or similar) for connecting to the inductor. Thus, multiple (different) inductors, e.g., inductors having different shapes, inductances, or other characteristics, can be selectively connected to the device of the 22nd embodiment and used as inductors.

[0270] In any embodiment described herein, the (first) inductor and / or the applicator in which the (first) inductor is housed may, for example, be of a generally flat structure such that the (first) inductor and / or the applicator may be applied to the body part from substantially one side. Other shapes or structure types are possible, for example a hollow cylinder or similar, whereby the windings of the (first) inductor may surround the body part, i.e. the (first) inductor or applicator may be applied onto the body part, or the body part (e.g. arm, leg, torso) may be introduced into or pass through the inductor or applicator.

[0271] Furthermore, the structure of any, some, or all of the inductors described in this application, in particular the (first) inductor, is not limited to a particular design. In particular, any, some, or all of the inductors, in particular the (first) inductor, may be fabricated such that, for example, each (360°) turn or winding of the respective inductor includes or consists of one solid (and substantially rigid) piece of conductive material (e.g. copper) rather than multiple strands running in parallel. Alternatively, each (360°) turn or winding of the respective inductor may include or consist of a small number (e.g. 2 or less, or 3 or less, or 4 or less, or 5 or less, etc.) of solid (and substantially rigid) pieces of conductive material (e.g. copper) insulated from each other. In other embodiments, any, some, or all of the inductors, in particular the first inductor, may be fabricated, for example, from Litz wire, with each wire separately insulated, in particular may include a Litz wire coil. This may reduce eddy currents in the inductor.

[0272] The various embodiments and advantages described above with respect to any one aspect of the present disclosure or the present invention apply to other aspects of the present disclosure or the present invention as well. Each feature disclosed and / or illustrated herein may be incorporated into the present invention, whether alone or in combination with any other feature disclosed or illustrated herein, unless such combination is expressly excluded or technically impossible. In particular, the first to twenty-second aspects (embodiments) may be combined with each other.

[0273] In particular, in accordance with the present invention, the following features (or any subset thereof): - from the first and / or second aspect, an additional inductor in the first or second branch in addition to the (first) inductor for generating a magnetic field to be applied to the body tissue, or a circuit in which the total inductance of the first branch is (significantly) different from the total inductance of the second branch; an additional inductor in series with the (first) inductor for generating a magnetic field to be applied to the body tissue according to the fifth aspect, said additional inductor having a variable inductance or provided with a bypass circuit for selectively bypassing or short-circuiting said additional inductor; a capacitor arrangement according to an eighth aspect, comprising at least one capacitor with a variable capacitance, a switching device of the first branch according to an eleventh aspect, which can be switched at a freely selectable time between a conducting state and a substantially non-conducting state, a first branch leading to a first inductor and a second branch leading to a second inductor according to a fourteenth aspect, It is possible to make a device comprising a circuit having a charging circuit according to the seventeenth aspect.

[0274] The same applies mutatis mutandis to the method according to any one or more of the third, sixth, ninth, twelfth, fifteenth and eighteenth aspects, as well as to the apparatus according to any one or more of the fourth, seventh, tenth, thirteenth, sixteenth and nineteenth aspects.

[0275] Although the device according to the twentieth aspect may differ somewhat structurally from the devices according to the first, second, fifth, eighth, eleventh, fourteenth and seventeenth aspects, it is nevertheless possible to fabricate a device having features according to the twentieth aspect and at least some of the other aspects disclosed herein. To give two examples, a device according to the twentieth aspect is provided, one or more additional inductors in series with any one or more of the switching devices (first aspect), or - one or more additional inductors in series with the (first) inductor to generate a magnetic field to be applied to the body tissue (fifth aspect) It would be possible to set up.

[0276] As stated, the embodiments disclosed herein may be used for therapeutic purposes, but may also be used for non-therapeutic purposes, including, but not limited to, affecting / altering the appearance of the human or animal body, particularly for cosmetic purposes, and testing devices on the human or animal body, as well as testing devices in the absence of a human or animal body.

[0277] Some embodiments of the invention are now described, by way of example only, with reference to the accompanying drawings. [Brief description of the drawings]

[0278] [Figure 1] FIG. 1 is a schematic diagram showing a circuit diagram of a device for generating an alternating magnetic field known to the inventor (but not admitted to be prior art); [Diagram 2] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 3] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 5] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Figure 6] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. [Figure 7] FIG. 2 is a plot of current through a first inductor versus time, according to one embodiment of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 9] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 10] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 11] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Figure 12] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. [Figure 13] FIG. 2 is a plot of current through a first inductor versus time, according to one embodiment of the present disclosure. [Figure 14] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 15] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 16] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 17] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 18] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Figure 19] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. [Figure 20] FIG. 2 is a plot of current through a (first) inductor versus time, according to one embodiment of the present disclosure. [Figure 21] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 22] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 23] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Figure 24] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. [Diagram 25] FIG. 2 is a plot of current through a (first) inductor versus time, according to one embodiment of the present disclosure. [Figure 26]FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 27] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Figure 28] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Figure 29] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Diagram 30] FIG. 2 is a plot of current through a first inductor and a second inductor versus time, according to one embodiment of the present disclosure. [Diagram 31] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. [Diagram 32] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 33] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 34] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 35] FIG. 2 is a schematic diagram showing a circuit diagram of a charging circuit of an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Diagram 36] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. [Figure 37] 4 is a plot of current through a first inductor and voltage across a capacitor versus time according to one embodiment of the present disclosure. FIG. [Figure 38] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Figure 39] FIG. 1 is a schematic diagram illustrating a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. [Diagram 40] FIG. 1 is a schematic diagram illustrating an apparatus for generating a magnetic field according to one embodiment of the present disclosure. [Diagram 41]FIG. 13 is a plot of current through an inductor versus time, according to one embodiment of the present disclosure. [Diagram 42] 1 is a flow chart illustrating a method according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0279] FIG. 2 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The circuit diagram shown in FIG. 2 is similar to the circuit diagram shown in FIG. 1. The above description of the device shown in FIG. 1 is therefore not repeated here, as it also applies to the circuit diagram shown in FIG. 2. Elements shown in FIG. 2 that correspond to elements shown in FIG. 1 are given the same reference numbers, reduced by 100. However, it should be noted that various modifications are possible. For example, in many embodiments, the source of electrical energy 7 (e.g., voltage source 7) may be a mains source, but may alternatively be a non-mains source, for example, including a battery or a battery arrangement including one or more batteries. The switching device 3 is illustrated as a thyristor, but as explained above, other switching devices may also be used. The electrical component 4 in the second branch 6 is illustrated as a diode, but as explained above, other electrical components or electrical component assemblies, in particular electronic components or electronic component assemblies, may be used. However, for the sake of brevity, the description of the circuit diagram shown in FIG. 2 continues to use the same terminology as used in connection with FIG. 1.

[0280] Furthermore, for the sake of better understanding, although a charging circuit including an electrical energy source 7 and a switching device 8 is illustrated, the present disclosure also includes embodiments that do not have such a charging circuit (but may be used in conjunction with, and in particular may be electrically connected to, such a charging circuit).

[0281] The second branch 6 shown in FIG. 2 includes a second inductor 9 connected in series with the diode 4. The current flowing between the first inductor 2 and the capacitor 1 through the second branch 6 also flows through the second inductor 9. Considering the current flowing through the first inductor 2 and the second branch 6 and the capacitor 1, the second inductor 9 is practically connected in series with the first inductor 2. Such an additional inductor does not form part of the first branch 5, and therefore the inductance of the second branch 6 is higher, in particular significantly higher, than the inductance of the first branch 5. It can therefore be seen that the frequency of the resonant circuit including the second branch 6 is (significantly) lower than the frequency of the resonant circuit including the first branch 5, when considering the capacitor 1, the first inductor 2 and either the first branch 5 or the second branch 6 as a resonant circuit.

[0282] FIG. 3 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 3 is similar to the embodiment shown in FIG. 2, and the same description given in relation to FIG. 2 also applies to the embodiment shown in FIG. 3. Similar parts are labeled with similar reference numbers. FIG. 3 additionally shows a circuit for bypassing or shorting the second inductor 9. This bypass circuit includes an additional switching device 10 connected to the two terminals of the second inductor 9 and enabling the bypass circuit to selectively bypass the second inductor 9. When the additional switching device 10 is in a closed state (or conducting state), any current flowing through the second branch 6 flows solely or (almost) exclusively through the bypass circuit, thereby substantially preventing current from flowing through the second inductor 9. In this way, the total inductance of the second branch 6 can vary between a maximum value (additional switching device 10 in an open state) and a minimum value (additional switching device 10 in a closed state). When the additional switching device 10 is closed, the inductance of the second branch 6 may be similar to the inductance of the first branch 5 .

[0283] FIG. 4 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 4 is similar to the embodiment shown in FIG. 3, and the same description given in relation to FIG. 3 also applies to the embodiment shown in FIG. 4. Similar parts are labeled with similar reference numbers. FIG. 4 additionally shows an additional inductor 11, which forms part of the second branch 6 and is connected in series with the second inductor 9 (and the diode 4). The circuit diagram shown in FIG. 4 additionally includes an additional circuit for bypassing or short-circuiting the additional inductor 11. This additional bypass circuit includes an additional switching device 12 connected to the two terminals of the additional inductor 11 and enabling the additional bypass circuit to selectively bypass the additional inductor 11. When the additional switching device 12 is in a closed state (or conducting state), any current flowing through the second branch 6 flows solely or (almost) exclusively through the additional bypass circuit, thereby substantially preventing current from flowing through the additional inductor 11. In this way, the total inductance of the second branch 6 can be changed.

[0284] By using the two additional switching devices 10 and 12, the total inductance of the second branch 6 can vary between a maximum value (both additional switching devices 10 and 12 are open or non-conducting) and a minimum value (both additional switching devices 10 and 12 are closed or conducting). When both additional switching devices 10 and 12 are closed, the inductance of the second branch 6 can be similar to the inductance of the first branch 5. When only one of the additional switching devices 10 and 12 is closed and the other is open, only one of the second inductor 9 and the additional inductor 11 is bypassed and therefore the total inductance of the second branch 6 is an intermediate value between the minimum and maximum values.

[0285] 4, the bypass circuit associated with either the second inductor 9 or the additional inductor 11 may be omitted. Thus, the respective inductor would be permanently connected in series with the diode 4, but the other of the second inductor 9 and the additional inductor 11 (whose bypass circuit is not omitted) may be selectively bypassed using its associated bypass circuit.

[0286] 4, still further inductors may be added to the second branch 6 in series with the diode 4, the second inductor 9, and the further inductor 11. Each of these further inductors may or may not have an associated bypass circuit similar to the bypass circuit associated with the second inductor 9 and the further inductor 11.

[0287] According to a variant of any of the embodiments described with reference to Figures 2, 3 and 4 (or any of the variants already described above), any one or more of the second inductor 9, the additional inductor 11 and still additional inductors (if provided) may comprise an inductor with a variable inductance. Details of the inductor with a variable inductance have already been described above.

[0288] In a further development of this variant, only one of the inductors in the second branch 6 is an inductor with a variable inductance, for example the second inductor 9. Nevertheless, by appropriately selecting the (maximum) inductance of the second inductor 9 and the inductances of the additional inductors in the second branch 6, the total inductance of the second branch 6 may be adjustable over a relatively wide range, in particular in small steps, or (substantially) continuously. In this further development, each of the additional inductors is provided with an associated bypass circuit. The second inductor 9 with a variable inductance may or may not be provided with an associated bypass circuit. If the inductance of the second inductor (L2) and the inductances of the additional inductors (L3, L4, L5, L6, etc.) are selected according to a ratio such as 1:1:2:4:8, the lowest value of the total inductance of the second branch 6 can be achieved if the third inductor (having inductance L3) and the additional inductors (having inductances L4, L5, L6, etc.) are bypassed and the variable inductance of the second inductor 9 (L2) is adjusted to a minimum value L2min. By adjusting the variable inductance L2 of the second inductor 9 over its adjustable range up to a maximum value L2max, the total inductance of the second branch 6 can be adjusted from L2min to L2max. If the third inductor (only) is not bypassed (and the fourth inductor and any additional inductors are bypassed), the total inductance of the second branch 6 can be adjusted from L3+L2min to L3+L2max by adjusting the variable inductance L2 of the second inductor 9 over its adjustable range. If the fourth inductor (only) is not bypassed (as well as the third, fifth and any additional inductors are bypassed), the total inductance of the second branch 6 can be adjusted from L4+L2min to L4+L2max. The next adjustable range of the total inductance can be achieved by not bypassing the third and fourth inductors, bypassing the fifth and any additional inductors, etc.If the relative inductances of the second inductor and the additional inductor are selected in accordance with the above ratio and further assuming that the variable inductance L2 of the second inductor 9 can be adjusted substantially down to zero (L2min=0), then the total inductance of the second branch 6 can be adjusted (in discrete steps or substantially continuously) from substantially zero up to a maximum total inductance corresponding to the sum of all the inductances of the inductors forming part of the second branch 6, i.e. L2max+L3+L4+L5, etc.

[0289] According to a further modification, which may be based on any of the above embodiments or modifications, the second and / or additional inductor (with an associated bypass circuit) is included in the first branch 5 rather than in the second branch 6.

[0290] FIG. 5 shows, in a schematic way, an apparatus for generating a magnetic field according to one embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 3. However, the charging circuit shown in FIG. 3 is not shown in FIG. 5. Instead, FIG. 5 shows a capacitor 1 and first and second branches 5 and 6 integrated in a housing or cabinet 16 (electrically insulated from the electrical components and circuits contained in the cabinet 16). Terminals 19 for connection to an external charging circuit are provided in the cabinet 16 for the purpose of charging the capacitor 1. In one variant, a charging circuit, for example as shown in FIG. 3, can also be integrated in the cabinet 16.

[0291] The cabinet 16 is provided with two additional terminals 17 and 18. Terminal 17 is connected to the first branch 5 and the second branch 6, and terminal 18 is connected to a common ground potential. In the embodiment shown in Figure 5, terminal 18 is connected to the ground connection for capacitor 1 via a line running inside the cabinet 16.

[0292] Figure 5 shows the first inductor 2 as a separate entity from the cabinet 16 and its contents. The first inductor 2 is housed within a casing 13, which is attached to a conduit tube 14. The conduit tube 14 houses a cable 15, which is electrically connected to the first inductor 2, and in particular to at least one set of turns of the inductor 2, and which may be connected to a terminal 17, as shown by the dashed line. In the embodiment shown in Figure 5, the inductor 2 may also be connected to a ground terminal 18 of the cabinet 16 via a second cable.

[0293] As a variant of the embodiment shown in Fig. 5, the first inductor 2 could also be connected to ground potential via a separate line, i.e. without via the cabinet 16. In this case, the ground terminal 18 and the internal connection to ground could be omitted.

[0294] In further variations, features of the embodiment shown in Figure 5 may be combined with the embodiments shown in Figures 2 and 4, or with any of the variations described herein. Furthermore, in any of the above embodiments or variations, any or all of the connections to ground may be omitted and replaced by electrical connections between different parts of the circuit. For example, in Figure 2, the three connections to ground (triangles toward the bottom of the figure) may be replaced by interconnects such that capacitor 1 (at the bottom in Figure 2), first inductor 2, and voltage source 7 are electrically connected.

[0295] In any of the above embodiments or variations, the polarity of the individual components may be reversed, so that, for example, the negative terminal of the voltage source 7 is connected to the first branch 5, the second branch 6, and the capacitor 1 via the switching device 8. The polarity of the thyristor 3 and the diode 4 would then also be reversed. Furthermore, as already mentioned, the inventors understand that the components and interconnections described in relation to the present disclosure are not "ideal" in the electrical sense. Enabled by the present disclosure, the skilled artisan can make appropriate adjustments to allow for this. This applies in particular, but not exclusively, to the variations described above, where inductors having inductances according to ratios such as 1:1:2:4:8 may be used. For example, appropriate adjustments may be made to take into account parasitic inductances.

[0296] FIG. 6 shows a flow chart illustrating a method according to an embodiment of the disclosure. After the start 90 of the method, any one of the apparatuses described above is provided (91). Electrical energy is then stored in an electric storage device, in particular a capacitor 1 (92). The switching device 3, in particular a thyristor 3, is then switched to a conductive or "ON" state (93) to electrically connect the electric storage device 1 to the first inductor 2. This causes a current caused by the electric energy stored by the electric storage device 1 to flow through the first branch 5 and through the first inductor 2, thereby causing the first inductor 2 to generate a magnetic field. This current flow may represent a first half-pulse or half-wave. At the end of the first half-pulse or half-wave, a current is then allowed to flow between the electric storage device 1 and the first inductor 2 through the second branch 6 via the electric component or electric component assembly 4 (94). This current flow may represent a second half-pulse or half-wave. Assuming that the second and any additional inductors 9, 11 are not bypassed or shorted, current also flows through the second and any additional inductors 9, 11 during this second half-pulse or half-wave. At the end of the second half-pulse or half-wave, the method may end (95). Alternatively, the method or parts thereof may be repeated. In particular, the switching device or thyristor 3 may again be switched to a conducting or "ON" state, etc. (93). Electrical energy may again be stored in the storage device 1 (92). In particular, the capacitor 1 may be recharged, for example to its initial charge state, to compensate for dissipation of electrical energy in the apparatus.

[0297] FIG. 7 shows a plot of the current through the first inductor 2 versus time, according to one embodiment of the disclosure. The resulting circuit shown in the diagram of FIG. 7 can be the circuit shown in FIG. 2, except that the second inductor 9 is placed in the first branch 5 (in series with the switching device 3) rather than in the second branch 6. The first half-pulse shown in FIG. 7 shows a slower rise and fall of the current through the first inductor 2 compared to the second half-pulse. This is due to the higher total inductance (total inductance=inductance of the first inductor 2+inductance of the second inductor 9) in the first half-pulse compared to the total inductance (total inductance=inductance of the first inductor 2) in the second half-pulse.

[0298] FIG. 8 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to one embodiment of the present disclosure. The circuit diagram shown in FIG. 8 is similar to the circuit diagram shown in FIG. 2. The above description of the device shown in FIG. 2 therefore also applies to the circuit diagram shown in FIG. 8 and is not repeated here. Where the elements shown in FIG. 8 have substantially the same function as the elements shown in FIG. 2, they are given the same reference numbers as in FIG. 2. Where the elements shown in FIG. 8 are generally similar to the elements shown in FIG. 2 but differ, for example in terms of function or position in the circuit, they are given reference numbers as in FIG. 2 but increased by 300.

[0299] In contrast to the embodiment shown in FIG. 2, the second branch 6 does not include an additional inductor that does not (also) form part of the first branch 5. Instead, the circuit shown in FIG. 8 includes a second inductor 309 connected in series with the first inductor 2. The current flowing between the first inductor 2 and the capacitor 1 also flows through the second inductor 309, regardless of whether the current flows through the first branch 5 or the second branch 6. In other words, the second inductor 309 is not only connected in series with the first inductor 2, but also with each of the switching device 3 and the diode 4 (or more precisely, with a parallel connection including the switching device 3 and the diode 4). It can also be said that the second inductor 309 forms part of both the first branch 5 and the second branch 6.

[0300] The total inductance of the (resonant) circuit between (including) the capacitor 1 and the first inductor 2 corresponds to the sum of the inductances of the first inductor 2 and the second inductor 309 (as well as any other inductances that may be present in the circuit, including parasitic inductances not shown in FIG. 8). The frequency of this (resonant) circuit is therefore different from the frequency of the (resonant) circuit shown in FIG. 1, i.e. the frequency if the second inductor 309 was not present. The frequency of the (resonant) circuit shown in FIG. 8 can therefore be influenced by choosing a different value of inductance for the second inductor 309.

[0301] FIG. 9 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 9 is similar to the embodiment shown in FIG. 8, and the same description given in relation to FIG. 8 also applies to the embodiment shown in FIG. 9. Similar parts are labeled with similar reference numbers. FIG. 9 additionally shows a circuit for bypassing or shorting the second inductor 309. This bypass circuit includes an additional switching device 310 connected to two terminals of the second inductor 309 and enabling the bypass circuit to selectively bypass the second inductor 309. When the additional switching device 310 is in a closed state (or conducting state), any current flowing through the first inductor 2 flows solely or (almost) exclusively through the bypass circuit, thereby substantially preventing the current from flowing through the second inductor 309. In this way, the total inductance of the (resonant) circuit between (and including) the capacitor 1 and the first inductor 2 can vary between a maximum value (additional switching device 310 open) and a minimum value (additional switching device 310 closed). When the additional switching device 310 is closed, the inductance of the (resonant) circuit can be similar to the inductance of the corresponding circuit portion of Figure 1 (i.e., as if the second inductor 309 was not present).

[0302] FIG. 10 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 10 is similar to the embodiment shown in FIG. 9, and the same description given in relation to FIG. 9 also applies to the embodiment shown in FIG. 10. Similar parts are labeled with similar reference numbers. FIG. 10 additionally shows an additional inductor 311 connected in series with the first inductor 2 and the second inductor 309. The current flowing between the first inductor 2 and the capacitor 1 also flows through the additional inductor 311, regardless of whether the current flows through the first branch 5 or the second branch 6. In other words, the additional inductor 311 is not only connected in series with the first and second inductors 2, 309, but also with each of the switching device 3 and the diode 4 (or more precisely, with a parallel connection including the switching device 3 and the diode 4). The circuit diagram shown in FIG. 10 additionally includes an additional circuit for bypassing or short-circuiting the additional inductor 311. This additional bypass circuit includes an additional switching device 312 connected to two terminals of the additional inductor 311 and enabling the additional bypass circuit to selectively bypass the additional inductor 311. When the additional switching device 312 is in a closed state (or conducting state), any current flowing through the first inductor 2 flows solely or (almost) exclusively through the additional bypass circuit, thereby substantially preventing current from flowing through the additional inductor 311. In this way, the total inductance of the resonant circuit can be changed.

[0303] By using the two additional switching devices 310 and 312, the total inductance of the resonant circuit can vary between a maximum value (both additional switching devices 310 and 312 are open or non-conducting) and a minimum value (both additional switching devices 310 and 312 are closed or conducting). When both additional switching devices 310 and 312 are closed, the total inductance of the resonant circuit can be similar to the inductance of the corresponding circuit portion of FIG. 1 (i.e., as if the second inductor 309 and the additional inductor 311 were not present). When only one of the additional switching devices 310 and 312 is closed and the other is open, only one of the second inductor 309 and the additional inductor 311 is bypassed, and therefore the total inductance of the resonant circuit is an intermediate value between the minimum and maximum values.

[0304] 10, the bypass circuit associated with either the second inductor 309 or the additional inductor 311 may be omitted. Thus, the respective inductor would be permanently connected in series with the first inductor 2, but the other of the second inductor 309 and the additional inductor 311 (whose bypass circuit is not omitted) may be selectively bypassed using its associated bypass circuit.

[0305] 10, still additional inductors may be added in series with the first and second inductors 2, 309 and the additional inductor 311 (and in series with the parallel connection including the switching device 3 and the diode 4). Each of these further inductors may or may not have an associated bypass circuit similar to the bypass circuit associated with the second inductor 309 and the additional inductor 311.

[0306] According to a variant of any of the embodiments described with reference to Figures 8, 9 and 10 (or any of the variants already described above), any one or more of the second inductor 309, the additional inductor 311 and any further inductors (if provided) may comprise an inductor having a variable inductance. Details of the inductor having a variable inductance have already been described above.

[0307] In a further development of this variation, only one of the inductors (the second inductor 309, the additional inductor 311, or the still additional inductors (if provided)) is an inductor with a variable inductance, for example the second inductor 309. Nevertheless, by appropriately selecting the (maximum) inductance of the second inductor 309 and the inductance of the additional inductor 311 and the still additional inductors, if provided, the total inductance of the resonant circuit may be adjustable over a relatively wide range, in particular in small steps, or (substantially) continuously. In this further development, each of the (still) additional inductors is provided with an associated bypass circuit. The second inductor 309 with a variable inductance may or may not be provided with an associated bypass circuit. If the inductance of the second inductor (L2) and the inductances of the additional inductors (L3, L4, L5, L6, etc.) are selected according to a ratio such as 1:1:2:4:8, the lowest value of the total inductance of the resonant circuit can be achieved when the third inductor (having inductance L3) and the additional inductors (having inductances L4, L5, L6, etc.) are bypassed and the variable inductance of the second inductor 309 (L2) is adjusted to a minimum value L2min. Then, by adjusting the variable inductance L2 of the second inductor 309 over its adjustable range to a maximum value L2max, the total inductance of the resonant circuit can be adjusted from L1+L2min to L1+L2max (L1 is the inductance of the first inductor 2). If the third inductor (only) is not bypassed (and the fourth inductor and any additional inductors are bypassed), the total inductance of the resonant circuit can be adjusted from L1+L3+L2min to L1+L3+L2max by adjusting the variable inductance L2 of the second inductor 309 over its adjustable range. If the fourth inductor (only) is not bypassed (and the third, fifth and any additional inductors are bypassed), the total inductance of the resonant circuit can be adjusted from L1+L4+L2min to L1+L4+L2max.The next adjustable range of the total inductance may be achieved by not bypassing the third and fourth inductors, bypassing the fifth and any additional inductors, etc. If the relative inductances of the second inductor 309 and the additional inductors are selected according to the ratios above, and further assuming that the variable inductance L2 of the second inductor 309 may be adjusted substantially down to zero (L2min=0), then the total inductance of the resonant circuit may be adjusted (in discrete steps or substantially continuously) from substantially L1 up to a maximum total inductance corresponding to the sum of all inductances of the resonant circuit, i.e., L1+L2max+L3+L4+L5, etc.

[0308] According to a further modification, which may be based on any of the embodiments described with reference to Figures 8 to 10 or their modifications, an additional inductor (with an associated bypass circuit, if applicable) may be included in the first branch 5 or the second branch 6, as described with reference to Figures 2 to 4 or their modifications.

[0309] FIG. 11 shows, in a schematic way, an apparatus for generating a magnetic field according to one embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 9. However, the charging circuit shown in FIG. 9 is not shown in FIG. 11. Instead, FIG. 11 shows a capacitor 1 and first and second branches 5 and 6 integrated in a housing or cabinet 16 (electrically insulated from the electrical components and circuits contained in the cabinet 16). Terminals 19 for connection to an external charging circuit are provided in the cabinet 16 for the purpose of charging the capacitor 1. In one variant, for example, a charging circuit as shown in FIG. 9 can also be integrated in the cabinet 16.

[0310] The cabinet 16 is provided with two additional terminals 17 and 18. Terminal 17 is connected to a second inductor 309 (and its associated bypass circuit) and through it also to the first branch 5 and the second branch 6, while terminal 18 is connected to a common ground potential. In the embodiment shown in Figure 11, terminal 18 is connected to the ground connection for capacitor 1 via a line running inside the cabinet 16.

[0311] Figure 11 shows the first inductor 2 as a separate entity from the cabinet 16 and its contents. The first inductor 2 is housed within a casing 13, which is attached to a conduit tube 14. The conduit tube 14 houses a cable 15, which is electrically connected to the first inductor 2, and in particular to at least one set of turns of the inductor 2, and which may be connected to a terminal 17, as shown by the dashed line. In the embodiment shown in Figure 11, the inductor 2 may also be connected to a ground terminal 18 of the cabinet 16 via a second cable.

[0312] 11, the first inductor 2 could also be connected to ground potential via a separate line, i.e. not via the cabinet 16. In this case, the ground terminal 18 and the internal connection to ground could be omitted.

[0313] In further variations, features of the embodiment shown in Figure 11 may be combined with features of the embodiments shown in Figures 8 and 10, or any of the variations described herein. Furthermore, in any of the above embodiments or variations, any or all of the connections to ground may be omitted and replaced by electrical connections between different parts of the circuit. For example, in Figure 8, the three connections to ground (triangles toward the bottom of the figure) may be replaced by interconnects such that capacitor 1 (at the bottom in Figure 8), first inductor 2, and voltage source 7 are electrically connected.

[0314] In any of the above embodiments or variations, the polarity of the individual components may be reversed, so that, for example, the negative terminal of the voltage source 7 is connected to the first branch 5, the second branch 6, and the capacitor 1 via the switching device 8. The polarity of the thyristor 3 and the diode 4 would then also be reversed. Furthermore, as already mentioned, the inventors understand that the components and interconnections described with respect to the present invention are not "ideal" in the electrical sense. Enabled by the present disclosure, the skilled artisan can make appropriate adjustments to allow for this. This applies in particular, but not exclusively, to the variations described above where inductors having inductances according to ratios such as 1:1:2:4:8 may be used. For example, appropriate adjustments may be made to take into account parasitic inductances.

[0315] In further modifications of the embodiments shown in Figures 8 to 11 or those modifications described above, the positions (in an electrical sense) of the second inductor 309 (together with any associated bypass circuit 310) and the parallel connection comprising the first branch 5 and the second branch 6 may be reversed such that the second inductor 309 is connected between the capacitor 1 and the parallel connection comprising the first branch 5 and the second branch 6. This may also apply to additional inductors. What is important is that with such modifications, the capacitor 1, the parallel connection comprising the first branch 5 and the second branch 6, the first inductor 2, the second inductor 309 and any additional inductors (such as the inductor 311) are connected in series.

[0316] FIG. 12 shows a flow chart illustrating a method according to an embodiment of the disclosure. After the start 390 of the method, any one of the devices described above with reference to FIG. 8 to FIG. 11 or their modifications is provided (391). Electrical energy is then stored in the storage device, in particular the capacitor 1 (392). The switching device 3, in particular the thyristor 3, is then switched to a conductive or "ON" state (393) to electrically connect the storage device 1 to the first inductor 2. This causes a current caused by the electrical energy stored by the storage device 1 to flow through the first branch 5, through the second inductor 309 (if not bypassed), through the first inductor 2, and, if applicable, through any additional inductors such as the additional inductor 311 (if not bypassed), thereby causing the first inductor 2 to generate a magnetic field. This current flow may represent a first half-pulse or half-wave. At the end of the first half-pulse or half-wave, current is then allowed to flow (394) through the electrical component or electrical component assembly 4 through the second branch 6 between the storage device 1 and the first inductor 2 (and also through the first and any additional inductors 309, 311 if not bypassed). This current flow may represent a second half-pulse or half-wave. At the end of the second half-pulse or half-wave, the method may end (395). Alternatively, the method or parts thereof may be repeated. In particular, the switching device or thyristor 3 may again be switched to a conducting or "ON" state, etc. (393). Electrical energy may again be stored in the storage device 1 (392). In particular, the capacitor 1 may be recharged to its initial charge state, for example to compensate for the dissipation of electrical energy in the apparatus.

[0317] FIG. 13 shows a diagram of the current through the first inductor 2 plotted against time according to one embodiment of the disclosure. The circuit that may result in the diagram of FIG. 13 may be the circuit shown in FIG. 9, whereby the additional switching device 310 is initially open, i.e., during the first half-pulse (so that the current through the first inductor 2 also flows through the second inductor 309). At the end of the first half-pulse, the additional switching device 310 is closed to short-circuit or bypass the second inductor 309. The first half-pulse shown in FIG. 13 shows a slower rise and fall of the current through the first inductor 2 compared to the second half-pulse. This is due to the higher total inductance in the first half-pulse (total inductance=inductance of the first inductor 2+inductance of the second inductor 309) when compared to the total inductance in the second half-pulse (total inductance=inductance of the first inductor 2).

[0318] FIG. 14 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to one embodiment of the present disclosure. The circuit diagram shown in FIG. 14 is similar to the circuit diagram shown in FIG. 2. Therefore, the above description of the device shown in FIG. 2 also applies to the circuit diagram shown in FIG. 14 and is not repeated here. Where the elements shown in FIG. 14 have substantially the same function as the elements shown in FIG. 2, they are given the same reference numbers as in FIG. 2. Where the elements shown in FIG. 14 are generally similar to the elements shown in FIG. 2 but differ, for example in terms of function or position in the circuit, they are given reference numbers as in FIG. 2 but increased by 400.

[0319] In contrast to the embodiment shown in Figure 2, the second branch 6 does not include an additional inductor that does not (also) form part of the first branch 5. Instead, the circuit shown in Figure 14 includes a capacitor 401 with a variable capacitance - in the same position in the circuit as Figure 2 has capacitor 1 (in Figure 2 this capacitor 1 is not specified as having a variable capacitance).

[0320] Capacitor 401 may in principle be any type of capacitor having a variable capacitance (in short, a variable capacitor). Although the symbol used for capacitor 401 in Figure 14 may typically only be used for one particular type of variable capacitor, it should be understood that this symbol is intended to represent any type of variable capacitor, including mechanically controlled variable capacitors and electrically controlled variable capacitors.

[0321] Although capacitor 401 is a single capacitor, it may still be considered as a capacitor arrangement 420. Further examples of capacitor arrangements including multiple capacitors are described with reference to Figures 15 to 18.

[0322] When the capacitance of capacitor 401 in Figure 14 changes, this changes the resonant frequency of the resonant circuit of which capacitor 401 is a part, i.e. the resonant circuit including capacitor 401, the (first) inductor 2 and the connection circuit connecting them (branches 5 and / or 6). Thus, if the circuit of Figure 14 is operated in a pulsed manner, the pulse duration changes as well.

[0323] FIG. 15 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 15 is similar to the embodiment shown in FIG. 14, and the same description given in relation to FIG. 14 also applies to the embodiment shown in FIG. 15. Similar parts are given similar reference numbers. FIG. 15 additionally shows an additional capacitor 421 connected in parallel to the capacitor 401. Thus, the capacitor arrangement 420 of FIG. 15 includes the capacitors 401 and 421. The (total) capacitance of the capacitor arrangement 420 of FIG. 15 corresponds to (or is similar to) the sum of the (individual) capacitances of the capacitors 401 and 421.

[0324] Capacitor 421 is shown as a variable capacitor, and the comments above regarding the symbol used for capacitor 401 also apply to capacitor 421. However, additional capacitor 421 does not necessarily have to have a variable capacitance--it could also have a fixed capacitance.

[0325] Varying the capacitance of capacitor 401 and / or capacitor 421 changes the total capacitance of capacitor arrangement 420 and therefore the resonant frequency of the resonant circuit of which capacitor arrangement 420 forms part.

[0326] In a variation of the embodiment shown in FIG. 15, an additional capacitor, in particular a capacitor having a variable capacitance, may be provided in addition thereto and connected in parallel to capacitor 401 .

[0327] FIG. 16 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 16 is similar to the embodiment shown in FIG. 15, and the same description given in relation to FIG. 15 also applies to the embodiment shown in FIG. 16. Similar parts are labeled with similar reference numerals. FIG. 16 additionally shows an additional switch or switching device 422 connected in series with an additional capacitor 421. The additional switching device 422 selectively establishes or breaks an electrical connection between the additional capacitor 421 and the capacitor 401. When the additional switching device 422 is in a closed state (or conducting state), the additional capacitor 421 is connected in parallel with the capacitor 401, and the (total) capacitance of the capacitor arrangement 420 of FIG. 16 corresponds (or is similar) to the sum of the (individual) capacitances of the capacitors 401 and 421. When the additional switching device 422 is open (or non-conducting), the (total) capacitance of the capacitor arrangement 420 of Figure 16 corresponds to (or is similar to) the (individual) capacitance of capacitor 401--as if the additional capacitor 421 were not present. In this way, by opening or closing (or selectively making) the additional switching device 422 non-conducting or conducting, the resonant frequency of the resonant circuit of which the capacitor arrangement 420 forms part can be changed.

[0328] In this embodiment, the additional capacitor 421 may have a fixed capacitance (as shown) or alternatively may have a variable capacitance. Furthermore, in one variation, the positions of the additional capacitor and the additional switching device 422 in the circuit are swapped, such that the additional switching device 422 is placed between the additional capacitor 421 and ground. Electrically, this does not make a significant difference, and therefore this variation is considered equivalent to the embodiment shown in FIG.

[0329] In the embodiment of FIG. 16, if the (maximum) capacitance of the capacitor 401 and the (maximum) capacitance of the additional capacitor 421 are selected to be the same, the total capacitance of the capacitor arrangement 420 can be varied over a range from the minimum capacitance of the capacitor 401 to the sum of the (maximum) capacitances of the capacitors 401 and 421. For example, if the capacitor 401 can be adjusted between 0 μF and 100 μF and the capacitor 421 has a (fixed) capacitance of 100 μF, the total capacitance of the capacitor arrangement 420 can be varied between 0 μF and 100 μF when the switching device 422 is in an open state (or non-conducting state) and between 100 μF and 200 μF when the switching device 422 is in a closed state (or conducting state). If the capacitor 401 is continuously variable between 0 μF and 100 μF, the total capacitance of the capacitor arrangement 420 in this example can be continuously varied between 0 μF and 200 μF.

[0330] In another example, if capacitor 401 can be adjusted between 0 μF and 100 μF and capacitor 421 has a (fixed) capacitance of 300 μF, the total capacitance of capacitor arrangement configuration 420 can vary between 0 μF and 100 μF when switching device 422 is in an open state (or non-conducting state), and between 300 μF and 400 μF when switching device 422 is in a closed state (or conducting state).

[0331] FIG. 17 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The embodiment shown in FIG. 17 is similar to the embodiment shown in FIG. 16, and the same description given in relation to FIG. 16 also applies to the embodiment shown in FIG. 17. Similar parts are labeled with similar reference numerals. FIG. 17 additionally shows a (still) additional capacitor 423 connected in parallel with the capacitor 401 (and in parallel with the additional capacitor 421). Thus, the capacitor arrangement 420 of FIG. 17 includes the capacitors 401, 421, and 423. FIG. 17 also shows a (further) additional switch or switching device 424 connected in series with the additional capacitor 423. The additional switching device 424 selectively establishes or breaks an electrical connection between the additional capacitor 423 and the capacitor 401 (and the additional capacitor 421). When the additional switching devices 422 and 424 are closed (or conducting), the additional capacitors 421 and 423 are connected in parallel to the capacitor 401 and the (total) capacitance of the capacitor arrangement 420 of FIG. 17 corresponds (or is similar) to the sum of the (individual) capacitances of the capacitors 401, 421 and 423. When the additional switching devices 422 and 424 are open (or non-conducting), the (total) capacitance of the capacitor arrangement 420 of FIG. 17 corresponds (or is similar) to the (individual) capacitance of the capacitor 401 (as if the additional capacitors 421 and 423 were not present). The same applies, mutatis mutandis, when only one of the switching devices 422 and 424 is closed (or conducting) and the other is open (or non-conducting). In this manner, by selectively opening or closing (or selectively rendering non-conductive or conductive) the additional switching devices 422 and / or 424, the resonant frequency of the resonant circuit of which the capacitor arrangement 420 forms part can be changed.

[0332] According to further modifications, the capacitor arrangement 420 may be expanded by adding still further capacitors and connecting them in parallel with the capacitor 401. These still further capacitors may have variable or fixed capacitances. In addition, still further switching devices may be connected in series with the still further capacitors, similar to that shown in FIG.

[0333] In a further development of this variation, only one of the capacitors (capacitor 401) has a variable capacitance (similar to that shown in FIG. 17), but still further capacitors (and their associated still further switching devices) are connected in parallel to capacitor 401. Nevertheless, by appropriately selecting the (maximum) capacitance of capacitor 401 and the capacitances of the further capacitors 421 and 423 and the further capacitors, the total capacitance of the capacitor arrangement, and thus the total capacitance of the resonant circuit (and thus also the resonant frequency of the resonant circuit) may be adjustable over a relatively wide range, in particular in small steps or (substantially) continuously. If the (maximum) capacitance C1 of capacitor 401 and the capacitances C2, C3 (Cm, where m=4, 5, 6, ...) of the additional capacitors 421 and 423 and further additional capacitors are selected according to a ratio such as 1:1:2:4:8, the lowest value of the total capacitance of the capacitor arrangement 420 can be achieved when all of the additional switching devices 422, 424 and further additional switching devices are open or non-conducting and the variable capacitance C1 of capacitor 401 is adjusted to a minimum value C1min. Then, by adjusting the variable capacitance C1 of capacitor 401 over its adjustable range up to a maximum value C1max, the total capacitance of the capacitor arrangement 420 can be adjusted from C1min to C1max. With the additional switching device 422 (only) closed or conducting (all other (still) additional switching devices 424 etc. open or non-conducting), the total capacitance of the capacitor arrangement 420 can be adjusted from C2+C1min to C2+C1max by adjusting the variable capacitance C1 of the capacitor 401 over its adjustable range. The next adjustable range of the total capacitance of the capacitor arrangement 420 can be achieved with the additional switching device 424 closed or conducting, and with the switching device 422 and all other still additional switching devices open or non-conducting.If the relative capacitances are selected according to the above ratios, and further assuming that the variable capacitance C1 of capacitor 401 can be adjusted substantially to zero (C1min=0 μF), then the total capacitance of capacitor arrangement portion 420 can be adjusted (in discrete steps or substantially continuously) from substantially 0 μF to a maximum total capacitance corresponding to the sum of all capacitances of capacitor arrangement portion 420, i.e. C1max+C2+C3+C4, etc.

[0334] According to a further modification, which may be based on any of the embodiments described with reference to Figures 14 to 17 or their modifications, an additional inductor (with an associated bypass circuit, if applicable), may in addition be included in the first branch 5 or the second branch 6, as described with reference to Figures 2 to 4 or their modifications, and / or in series with the first inductor 2, as described with reference to Figures 8 to 10 or their modifications.

[0335] FIG. 18 shows in schematic form an apparatus for generating a magnetic field according to one embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 17. However, the charging circuit shown in FIG. 17 is not shown in FIG. 18. Instead, FIG. 18 shows a capacitor arrangement 420 and first and second branches 5 and 6 integrated into a housing or cabinet 16 (electrically insulated from the electrical components and circuits contained in the cabinet 16). Terminals 19 for connection to an external charging circuit are provided in the cabinet 16 for the purpose of charging the capacitor arrangement 420. In one variant, for example, a charging circuit as shown in FIG. 17 may also be integrated into the cabinet 16.

[0336] The cabinet 16 is provided with two additional terminals 17 and 18. Terminal 17 is connected to the first branch 5 and the second branch 6, and terminal 18 is connected to a common ground potential. In the embodiment shown in Figure 18, terminal 18 is connected to a ground connection to the capacitor arrangement 420 via a line running inside the cabinet 16.

[0337] Figure 18 shows the first inductor 2 as a separate entity from the cabinet 16 and its contents. The first inductor 2 is housed within a casing 13, which is attached to a conduit tube 14. The conduit tube 14 houses a cable 15, which is electrically connected to the first inductor 2, and in particular to at least one set of turns of the inductor 2, and which may be connected to a terminal 17, as shown by the dashed line. In the embodiment shown in Figure 18, the inductor 2 may also be connected to a ground terminal 18 of the cabinet 16 via a second cable.

[0338] 18, the first inductor 2 could also be connected to ground via a separate line, i.e. not via the cabinet 16. In this case, the ground terminal 18 and the internal connection to ground could be omitted.

[0339] In further variations, features of the embodiment shown in Figure 18 may be combined with features of the embodiment shown in Figures 14 to 16 or any of the variations described herein. Furthermore, in any of the above embodiments or variations, any or all of the connections to ground may be omitted and replaced by electrical connections between different parts of the circuit. For example, in Figures 14 to 17, the three connections to ground (triangles toward the bottom of the figures) may be replaced by interconnections such that the capacitors of the capacitor arrangement 420 (at the bottom in Figures 14 to 17), the first inductor 2, and the voltage source 7 are electrically connected.

[0340] In any of the above embodiments or variations, the polarity of the individual components may be reversed, so that, for example, the negative terminal of the voltage source 7 is connected to the first branch 5, the second branch 6 and the capacitor arrangement 420 via the switching device 8. The polarity of the thyristor 3 and the diode 4 would then also be reversed. Furthermore, as already mentioned, the inventors understand that the components and interconnections described with respect to the present invention are not "ideal" in the electrical sense. Enabled by the present disclosure, the skilled artisan can make appropriate adjustments to allow for this. This applies in particular, but not exclusively, to the variations described above where capacitors having capacitances according to ratios such as 1:1:2:4:8 may be used. For example, appropriate adjustments may be made to take into account parasitic capacitances.

[0341] FIG. 19 shows a flow chart illustrating a method according to an embodiment of the present disclosure. After the start 490 of the method, any one of the devices described above with reference to FIG. 14 to FIG. 18 or their modifications is provided (491). Electrical energy is then stored in the capacitor arrangement 420, in particular the capacitor 401 (492). The switching device 3, in particular the thyristor 3, is then switched to a conductive or "ON" state (493) to electrically connect the capacitor arrangement 420 to the first inductor 2. This causes a current caused by the electrical energy stored by the capacitor arrangement 420 to flow through the first branch 5 and through the first inductor 2, thereby causing the first inductor 2 to generate a magnetic field. This current flow may represent a first half-pulse or half-wave. At the end of the first half-pulse or half-wave, current is then allowed to flow (494) through the electrical component or electrical component assembly 4 through the second branch 6 between the capacitor arrangement 420 and the first inductor 2. This current flow may represent a second half-pulse or half-wave. At the end of the second half-pulse or half-wave, the method may end (495). Alternatively, the method or parts thereof may be repeated. In particular, the switching device or thyristor 3 may again be switched to a conducting or "ON" state, etc. (493). Electrical energy may again be stored in the capacitor arrangement 420 (492). In particular, the capacitor arrangement 420 may be recharged to its initial charge state, for example to compensate for dissipation of electrical energy in the device.

[0342] As an optional additional step (not shown in FIG. 19), the capacitance of the capacitor arrangement 420 can be changed either during the first or second half-pulse, or between the first and second half-pulses, or between the first (full) pulse and the next pulse, as described above.

[0343] FIG. 20 shows a diagram in which the current through the first inductor 2 is plotted against time, according to one embodiment of the present disclosure. The circuit that can be shown as the diagram of FIG. 20 as a result can be the circuit shown in FIG. 14, whereby the capacitance of the capacitor 401 can initially take a first capacitance value, i.e. during the first half-pulse 430. The first half-pulse 430 has a corresponding first duration. At the end of the first half-pulse 430, the capacitance of the capacitor 401 is changed to a second capacitance value, which is lower than the initial capacitance value. This increases the resonant frequency of the resonant circuit of which the capacitor 401 is a part. The second half-pulse 431 therefore has a second duration, which is shorter than the first duration (of the first half-pulse 430).

[0344] FIG. 21 shows, in a schematic form, a circuit diagram of an apparatus for generating a magnetic field according to an embodiment of the present disclosure. The circuit diagram shown in FIG. 21 is similar to the circuit diagram shown in FIG. 2 and other figures. Therefore, the above description of the device shown in FIG. 2 (and other figures) also applies to the circuit diagram shown in FIG. 21 and will not be repeated here. Where elements shown in FIG. 21 have substantially the same function as elements shown in FIG. 2 and other figures, they are given the same reference numbers as in FIG. 2 (and other figures). Where elements shown in FIG. 21 are generally similar to elements shown in FIG. 2 but differ, for example, in terms of function or position in the circuit, they are given reference numbers as in FIG. 2 but increased by 500.

[0345] In contrast to the embodiment shown in FIG. 2, the second branch 6 of FIG. 21 does not include an additional inductor that does not (also) form part of the first branch 5. Moreover, while the second branch 6 of the embodiment of FIG. 2 included an electric component 4 such as a diode, the embodiment of FIG. 21 includes a spark gap 542 and a resistor 543 (connected in series with the spark gap 542) in the second branch. In addition to that, the switching device 3 is of a type that can be switched on (or transition from a non-conducting state to a conducting state) as well as switched off (or transition from a conducting state to a non-conducting state). For this, a (first) controller 540 is provided. The switching device 3 is controlled by the controller 540 such that the switching device 3 is switched on and off at desired times. In particular, the switching device 3 can be switched off at a time that does not coincide with the end of the first half-pulse (assuming that the circuit shown in FIG. 21 is operated in a pulsed manner). The switching device 3 may include, for example, an insulated gate bipolar transistor (IGBT), a field effect transistor (FET), a metal oxide semiconductor field effect transistor (MOSFET), or a gate turn-off thyristor (GTO thyristor). The controller 540 may include an analog circuit or a microcontroller.

[0346] Next, the operation of the circuit shown in FIG. 21 will be described by way of example, with further reference to FIG. 24, which shows a flow chart illustrating a method according to an embodiment of the present disclosure. The operation may be as follows: After the start 590 of the method, an apparatus having a circuit corresponding to the circuit shown in FIG. 21 (or any of the variations described herein) is presented (591). Electrical energy is then stored in the capacitor arrangement 420 (represented by capacitor 1 in FIG. 21) (592). Then, at a first time point, the switching device 3 is switched (593) to a conductive or "ON" state under the control of the controller 540, electrically connecting the capacitor arrangement 420 to the inductor 2. This causes a current caused by the electrical energy stored by the capacitor arrangement 420 to flow through the first branch 5 and through the inductor 2, thereby causing the inductor 2 to generate a magnetic field. This current flow may represent a first half-pulse or half-wave. However, the current flow may be interrupted at a selected second time point. To this end, at a first time point, the switching device 3 is switched (594) under the control of the controller 540 to a non-conducting or "OFF" state to electrically disconnect the capacitor arrangement 420 from the inductor 2. The second time point may be, for example, during the first half-pulse.

[0347] When the switching device 3 is in a non-conducting state, current may no longer flow through the switching device 3. However, the magnetic field already generated (by the inductor 2) resists its decay, i.e. the current continues to flow through the inductor 2, resulting in a (relatively high) voltage in the first and second branches 5, 6. Eventually, this voltage is high enough to cause the spark gap 542 to become conductive (595), thereby allowing current to flow through the second branch 6 via the resistor 543 and the spark gap 542 between the capacitor arrangement 420 and the inductor 2. The energy stored in the magnetic field is then at least partially dissipated in the resistor 543. The method may then end (596). Alternatively, the method or parts thereof may be repeated. In particular, the switching device 3 may again be switched (593) into a conducting or "ON" state, etc. Electrical energy may again be stored (592) in the capacitor arrangement 420. In particular, the capacitor arrangement 420 may be recharged to its initial charge state, for example to compensate for dissipation of electrical energy within the device.

[0348] 21 and 24, the spark gap 542 may protect the switching device 3 from damage or destruction, especially if it is configured to be conductive at a voltage U2, which is lower than the voltage U3 at which the switching device 3 would be damaged or destroyed. On the other hand, the spark gap 542 should not already be conductive at the voltage U1 to which the capacitor arrangement 420 is (should be) charged.

[0349] In variations (not specifically illustrated), other electrical circuit elements (some of which would normally be classified as passive circuit elements) may be used in place of the spark gap 542, particularly transient voltage suppression diodes, Zener diodes, Shockley diodes, triodes for alternating current (TRIACs), or thyristors, particularly in combination with a trigger circuit connected to or forming part of the second branch for triggering the thyristor.

[0350] Figure 22 illustrates a variation of the embodiment of Figure 21. Instead of the spark gap 542, an active electrical circuit element 503 or arrangement of circuit elements is included in the second branch 6, in particular a switching element 503 that is controlled by an analog circuit or a microcontroller (or is controlled by a second controller 541 that includes an analog circuit or a microcontroller). The use of the controller 541 allows a user to actively control the electrical circuit element 503, rather than the electrical circuit element 503 simply being allowed to become conductive or non-conductive depending on the voltage applied to two terminals in the second branch 6.

[0351] FIG. 23 illustrates a further development of the embodiment of FIG. 22. In the embodiment of FIG. 23, the device comprises a control unit 544 for controlling the first controller 540 and the second controller 541. To this end, the control unit 544 is connected to the first and second controllers 540, 541 (shown by dashed lines). In this way, any, some or all time points at which the switching device 3 and / or the switching element 503 are switched from a non-conducting state to a conducting state and vice versa can be controlled via the control unit 544. In particular, the first and / or second time points for switching the switching device 3 on and off can be selected via the control unit 544. Similarly, the third and / or fourth time points for switching the switching element 503 on and off can be selected via the control unit 544.

[0352] To allow a user to select any of the first through fourth time points, the control unit 544 may have one or more dials 545 and / or any other (user) interface, such as a touch screen 546. The control unit 544 may further comprise a processor / memory 547.

[0353] In one variant (not specifically illustrated), the control unit 544 is directly connected to the switching devices 3 and / or the switching elements 503 in order to control them, in which case the controllers 540 and / or 541 may be omitted.

[0354] In a further variant (not specifically illustrated), the apparatus may further comprise one or more detectors for making measurements at one or more locations in the circuit shown in FIG. 23, such as the voltage across the terminals of the switching device 3 in the first branch 5 and / or the voltage across the terminals of the switching element 503 in the second branch 6. These measurements may be transmitted to the control unit 544. Depending on the measurements made, the control unit 544 may set any of the first to fourth time points in order to protect any element of the circuit, such as, for example, the switching device 3 and / or the switching element 503, from damage or destruction.

[0355] Fig. 23 shows a further development of the circuit. This further development includes a detector 548. The detector 548 is intended to detect neural or cellular physiological responses, particularly muscle responses, in body tissue - represented in Fig. 23 by a human arm 551 - but the detector 548 can be used with any other body part of a human or animal. The detector 548 is also connected to a control unit 544, as shown by the dashed line. The operation of this further development will be explained with further reference to Fig. 25.

[0356] Figure 25 shows a number of curves in which the current (I) through the inductor 2 is plotted over time (t). Curve 549 follows a sinusoidal shape and represents the current through the inductor 102 of Figure 1 under ideal conditions during the first half-pulse. It therefore also represents the current through the inductor 2 of Figure 23 if the switching device 3 is not switched to a non-conducting state during the first half-pulse (i.e. if the second time point is not before the end of the first half-pulse).

[0357] When inductor 2 is applied to body tissue 551, the magnetic field generated by inductor 2, as described above, induces a current in the body tissue. This current in the body tissue at least approximately follows the same shape as the current through inductor 2, albeit at a (significantly) reduced level and out of phase. Thus, the current in the body tissue can be considered to be (approximately) proportional to (but out of phase with) the current through inductor 2.

[0358] FIG. 25 shows four additional curves, 550a to 550d, which show the current through the inductor 2 when the switching device 3 is switched to the non-conducting state before the end of the first half-pulse at a "second time point" t1 to t4, respectively. The "first time point" corresponds to the origin of the graph. In each case, the switching of the switching device 3 to the non-conducting state results in a relatively steep drop in the current. That is, initially, the current through the inductor 2 - after the first time point (i.e. the origin), when the switching device 3 is switched to the conducting state - follows a sinusoidal shape 549. After the "second time point" t1 to t4, the current continues along the curves 550a to 550d, respectively. These further curves 550a to 550d therefore represent different scenarios depending on when the switching device 3 is switched to the non-conducting state.

[0359] For curves 550a to 550c, the current reaches a maximum of I1 to I3, respectively. By varying the second point in time, particularly within the first quarter pulse (i.e., up to the time corresponding to the maximum of the sine wave shape 549), the maximum current reached (through inductor 2 and also in the body tissue) can be varied.

[0360] As already mentioned, the detector 548 is intended to detect a neural or cellular physiological response, particularly a muscular response, in the body tissue. If the current in the body tissue is low enough, the detector 548 will not detect any neural or cellular physiological response, particularly a muscular response. Looking at the graph shown in FIG. 25, this would correspond to a situation where the time interval between the first time point (origin) and the second time point (e.g., t1) is very short. By increasing the time interval, the current in the body tissue will also increase, and finally, a neural or cellular physiological response, particularly a muscular response, will be detected by the detector 548. For example, a neural or cellular physiological response (not a muscular response) may be detected when the time interval ends at t2, and a muscular response will be detected when the time interval ends at t3.

[0361] The detection result, i.e. whether a neural or cellular physiological response, in particular a muscular response, has been detected by the detector 548, may be transmitted from the detector 548 to the control unit 544, in particular to the processor / memory 547. The processor / memory 547 may process this information as well as information regarding the applicable time interval (or second time point) in order to determine the (shortest) time interval during which a neural or cellular physiological response, in particular a muscular response, may be detected.

[0362] Curve 550d is not very useful for determining the (shortest) time interval in which a neural or cellular physiological response, especially a muscular response, can be detected, since t4 is within the second 1 / 4 pulse, i.e. the maximum current (according to sine function 549) has already been reached before t4.

[0363] In further variations, features of the embodiments shown in Figures 21 to 23 may be combined with features of the embodiments shown in Figures 2 to 4, 8 to 10, 14 to 17, or any of the variations described herein. Furthermore, any of the above embodiments or variations may be adapted in a similar manner to that shown in and described with respect to Figures 5, 11 and 18, in particular to provide an apparatus according to Figures 21 to 23, but providing this apparatus with terminals 17, 18 and / or 19 for connection to inductor 2 and / or an external charging circuit, respectively.

[0364] In any of the above embodiments or variations, the polarity of the individual components may be reversed, so that, for example, the negative terminal of the voltage source 7 is connected via the switching device 8 to the first branch 5, the second branch 6 and the capacitor arrangement 420.

[0365] FIG. 26 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to one embodiment of the present disclosure. The circuit diagram shown in FIG. 26 is similar to the circuit diagram shown in FIG. 2. Therefore, the above description of the device shown in FIG. 2 also applies to the circuit diagram shown in FIG. 26 and is not repeated here. Where the elements shown in FIG. 26 have substantially the same function as the elements shown in FIG. 2, they are given the same reference numbers as in FIG. 2. Where the elements shown in FIG. 26 are generally similar to the elements shown in FIG. 2, but differ, for example in terms of function or position in the circuit, they are given reference numbers as in FIG. 2, but increased by 600.

[0366] In contrast to the embodiment shown in Figure 2, the first inductor 2 is connected to or forms part of the first branch 5, but not connected to or forming part of the second branch 6. Similarly, a second inductor 609 is provided, which is connected to or forms part of the second branch 6, but not connected to or forming part of the first branch 5. The two branches 5, 6 are substantially separate, except that they are both connected to an energy storage device 1 (again represented by a capacitor 1) and that they are both connected to a common ground potential (small triangle towards the bottom of the figure).

[0367] The first branch 5 also includes a switching device 3, and the above description of possible types of switching devices also applies to the embodiment of FIG. 26. The second branch 6 also includes a switching device 603, and the above description of possible types of switching devices also applies to the switching device 603. The first and second switching devices 3, 603 can be of the same type or of different types. In FIG. 26, as an example, the first switching device 3 and the second switching device 603 are shown as thyristors. The polarity of the first switching device 3 is such that it allows current to flow substantially only in one direction, which represents a first current direction of current flow for the storage device 1. The polarity of the second switching device 603 is such that it allows current to flow substantially only in one direction, which represents a second current direction of current flow for the storage device 1. The second current direction of current flow for the storage device 1 is opposite to the first current direction.

[0368] The operation of the circuit shown in FIG. 26 will now be described, by way of example, with further reference to FIG. 30 and FIG. 31. FIG. 30 shows a graph in which the current (I) through the first inductor 2 and the second inductor 609 is plotted over time (t). The graph in FIG. 30 can be considered as the current between the storage device 1 and the point where the first and second branches 5, 6 are connected. FIG. 31 shows a flow chart illustrating a method according to an embodiment of the present disclosure. The operation may be as follows: After the start 690 of the method, an apparatus is presented (691) having a circuit corresponding to the circuit shown in FIG. 26 (or any of the variations described herein). Electrical energy is then stored (692) in the storage device 1. Then, at a first time t1, the switching device 3 is switched (693) to a conducting or "ON" state, for example under the control of a suitable controller (such as the controllers described herein for other embodiments), to electrically connect the storage device 1 to the first inductor 2. This causes a current caused by the electrical energy stored by the storage device 1 to flow through the first branch 5 and through the first inductor 2, thereby causing the first inductor 2 to generate a first magnetic field. This current flow may represent a first half-pulse or half-wave 620.

[0369] At the end of the first half-pulse 620, i.e. at the second time point t2, the first magnetic field generated by the first inductor 2 has substantially decreased to zero and the storage device 1 has reached a maximum charge, albeit of opposite polarity compared to the initial state (just before t1). The absolute value of this maximum charge at t2 may be somewhat lower than the absolute value of the initial maximum charge (just before t1).

[0370] At a third time point t3, the switching device 603 is switched (694) to a conducting or “ON” state, e.g., under control of a suitable controller (such as a controller described herein with respect to other embodiments), to electrically connect the power storage device 1 to the second inductor 609. This causes a current caused by the electrical energy stored by the power storage device 1 to flow through the second branch 6 and through the second inductor 609, thereby causing the second inductor 609 to generate a second magnetic field. This current flow may represent a second half-pulse or half-wave 630.

[0371] At the end of the second half-pulse 630, i.e. at a fourth time t4, the second magnetic field generated by the second inductor 2 has substantially decreased to zero and the storage device 1 has reached a maximum charge of the same polarity as in the initial state immediately before t1 (albeit at a somewhat reduced level, assuming that some loss of energy has occurred in the device between t1 and t4). The method may then end (695). Alternatively, the method or parts thereof may be repeated. In particular, the first switching device 3 may again be switched to a conducting or "ON" state, etc. (693). Electrical energy may again be stored in the storage device 1 (692). In particular, the capacitor 1 may be recharged to its initial charge state, for example to compensate for the dissipation of electrical energy in the device.

[0372] As can be seen from the above description, the two half-pulses 620, 630 shown in FIG. 30 relate to different inductors 2, 609, respectively. While current flows between t1 and t2 through the first inductor 2, there is (substantially) no current flowing through the second inductor 609. While current flows between t3 and t4 through the second inductor 609, there is (substantially) no current flowing through the first inductor 2. Furthermore, from FIG. 30 and the above description, it will be seen that the delay between t2 and t3 can in particular be substantially freely selected, in particular by the user or the manufacturer. In particular, the delay between t2 and t3 can be longer or shorter than or of the same duration as the time interval between t1 and t2. The two points in time t2 and t3 can also be selected to be (substantially) coincident.

[0373] It will also be appreciated that the first and second inductances of the first and second inductors 2, 609, respectively, may or may not be the same. In the example of FIG. 30, the second inductance of the second inductor 609 is less than the first inductance of the first inductor 2. Thus, the time between t3 and t4 is less than the time between t1 and t2.

[0374] FIG. 27 shows in schematic form an apparatus for generating a magnetic field according to one embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 26. FIG. 27 shows (part of) the first and second branches 5 and 6 with the capacitor 1, the charging circuit including the electric energy source 7 and the switching device 8, as well as the first and second switching devices 3, 603 integrated into the housing or cabinet 16 (electrically insulated from the electric components and circuits housed by the cabinet 16). The first inductor 2 is housed in the first casing 13. The second inductor 609 is housed in the second casing 613. The first casing 13 is movable independently from the second casing 613. Both are movable with respect to the cabinet 16 and can be electrically connected to the rest of the circuit by a flexible cable.

[0375] Fig. 28 shows in schematic form an apparatus for generating a magnetic field according to one embodiment of the present disclosure. It is closely based on the embodiment shown in Fig. 27. However, in contrast to the embodiment of Fig. 27, both inductors 2, 609 are housed in the same casing 13 and are therefore not movable relative to each other. The casing 13 may be movable relative to the cabinet 16. The first and second inductors 2, 609 may again be electrically connected to the rest of the circuit by a flexible cable. The cable may for example be arranged in a single conduit tube (not shown).

[0376] FIG. 29 shows, in a schematic way, an apparatus for generating a magnetic field according to an embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 28. However, in contrast to the embodiment of FIG. 28, the first and second inductors 2, 609, as well as the casing 13 in which they are housed, are provided as separate units for connection to the cabinet 16. For this purpose, the cabinet 16 is provided with a number of terminals. In the example shown in FIG. 29, there are four such terminals: terminals 17, 18 for electrical connection to the first inductor 2 and terminals 617, 618 for electrical connection to the second inductor 609. Depending on the structure of the first and second inductors 2, 609 and any cables 15 connecting the first and second inductors 2, 609 to the rest of the circuit, a different number of terminals may be provided on the cabinet 16. FIG. 29 also shows a conduit tube 14 in which the cables 15 may be arranged.

[0377] Within cabinet 16, terminal 17 is connected to first switching device 3 and terminal 18 is connected to the ground connection of capacitor 1 via a wire running within cabinet 16. Similarly, terminal 617 is connected to second switching device 603 and terminal 618 is again connected to the ground connection of capacitor 1.

[0378] FIG. 29 shows the first and second inductors 2, 609 housed in the same casing 13, however, they may be housed in separate casings and movable relative to each other, similar to the embodiment of FIG. 27.

[0379] In a variation of the embodiment of Figures 27 to 29, the charging circuit (including the electrical energy source 7 and the switching device 8) or part of it may be provided separately (i.e. not within the cabinet 16), as shown, for example, in Figures 5, 11 and 18, in which case the cabinet 16 is provided with additional terminals 19 for connection to an external charging circuit.

[0380] In further variations, features of the embodiments shown in Figures 26 to 29 may be combined with features of the embodiments shown in Figures 2 to 5, 8 to 11, 14 to 18, and 21 to 23, or with features of any variations described herein.

[0381] FIG. 32 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to one embodiment of the present disclosure. The circuit diagram shown in FIG. 32 is similar to the circuit diagram shown in FIG. 2. Therefore, the above description of the device shown in FIG. 2 also applies to the circuit diagram shown in FIG. 32 and is not repeated here. Where elements shown in FIG. 32 have substantially the same function as elements shown in FIG. 2, they are given the same reference numbers as in FIG. 2. Where elements shown in FIG. 32 are generally similar to elements shown in FIG. 2 but differ, for example in terms of function or position in the circuit, they are given reference numbers as in FIG. 2 but increased by 700.

[0382] In contrast to the embodiment shown in FIG. 2, the second branch 6 of the circuit of FIG. 32 does not include an additional inductor that does not (also) form part of the first branch 5. Instead, the circuit shown in FIG. 32 includes a second voltage source 707 and an associated second switch or switching device 708 as part of a charging circuit 765 for charging the capacitor arrangement 420 including at least one capacitor 1. In FIG. 32, the capacitor arrangement 420 is again represented by a single capacitor 1, but as described with respect to the other embodiments, the capacitor arrangement 420 may include an additional capacitor. The charging circuit 765 also includes a (first) voltage source 7 and an associated switch or switching device 8. The circuit shown in FIG. 32 further comprises a control unit 544 for controlling the switching devices 3, 8, 703 and 708, as indicated by the dashed arrows.

[0383] 32, a second voltage source 707 is connected between its associated second switching device 708 and a common ground connection (small triangle at the bottom of the figure), but of opposite polarity when compared to the first voltage source 7. As a result, when the first switching device 8 is in a conducting state (when the second switching device 708 is in a non-conducting state), the first voltage source 7 charges the capacitor 1 with a first polarity. When the second switching device 708 is in a conducting state (and the first switching device 8 is in a non-conducting state), the second voltage source 707 charges the capacitor 1 with a second polarity opposite to the first polarity.

[0384] The operation of the circuit shown in Fig. 32 will now be described, by way of example, with further reference to Fig. 36 and Fig. 37. Fig. 36 shows a flow chart illustrating a method according to one embodiment of the present disclosure. Fig. 37 shows a graph in which the current (I) through inductor 2 is plotted over time (t). In Fig. 37, the current through inductor 2 is represented by a first half-pulse 720 and a second half-pulse 730. The current through inductor 2 also flows to / from capacitor 1.

[0385] FIG. 37 also shows the voltage (U) across capacitor 1 , as represented by the line labeled with reference numeral 732 .

[0386] The operation of the circuit of Fig. 32 may be as follows: After the start 790 of the method, an apparatus is presented (791) having a circuit corresponding to the circuit shown in Fig. 32. The first voltage source 7 then charges the capacitor 1 with a first polarity. To this end, the first switching device 8 is switched to a conducting state while the second switching device 708 is in a non-conducting state. This initial charging process is not explicitly shown in Fig. 37, but it results in the voltage across the capacitor 1 reaching a level of +U1 as shown at the left edge of Fig. 37.

[0387] Then, at a first time point t1, the switching device 3 is switched (793) to a conducting or "ON" state, for example under the control of a suitable controller (such as the control unit 544 described herein with respect to other embodiments), to electrically connect the power storage device 1 to the inductor 2. This causes a current caused by the electrical energy stored by the capacitor 1 to flow through the first branch 5 and through the inductor 2, thereby causing the inductor 2 to generate a magnetic field. This current flow results in a first half-pulse or half-wave 720. At this time, the first and second switching devices 8, 708 are in a non-conducting state.

[0388] At the end of the first half-pulse 720, i.e. at a second time t2, the magnetic field generated by the inductor 2 has substantially decreased to zero. The energy stored in the magnetic field (or most of it) has been returned to the capacitor 1, so that the capacitor 1 has reached a certain level of charge corresponding to a voltage U2, which is of opposite polarity compared to the initial state (just before t1). In addition, the absolute value of the voltage |-U2| at t2 is expected to be somewhat lower than the absolute value |+U1| of the initial maximum voltage (just before t1) due to energy losses in the circuit. If the second half-pulse 730 were allowed to start at this stage, it would typically have a smaller magnitude than the first half-pulse 720, and would eventually result in a net charge displacement in the body tissue to which the magnetic field is applied.

[0389] With this in mind, the present embodiment contemplates (re)charging (794) the capacitor 1, starting at or around the second time point t2, in particular to a voltage corresponding to (but having the opposite polarity) the initial voltage. For this purpose, the second switching device 708 is switched to a conductive state (while the first switching device 8 is in a non-conductive state) so as to electrically connect the second voltage source 707 to the capacitor 1. This recharging process is shown between the second time point t2 and the third time point t3 in FIG. 37. During this time interval, the absolute value of the voltage across the capacitor 1 increases from |-U2| to |-U1|.

[0390] At a third time point t3, the switching device 703 is switched (795) to a conducting or "ON" state, for example under the control of a suitable controller (such as the control unit 544), to electrically connect the power storage device 1 to the inductor 2. This causes a current caused by the electrical energy stored by the capacitor 1 to flow through the second branch 6 to the inductor 2, thereby causing the inductor 2 to generate a magnetic field. This results in a second half-pulse or half-wave 730. At this time, the first and second switching devices 8, 708 are in a non-conducting state.

[0391] At the end of the second half-pulse 730, i.e. at a fourth time t4, the magnetic field generated by the inductor 2 has substantially decreased to zero. The energy stored in the magnetic field (or most of it) has been returned to the capacitor 1, so that the capacitor 1 reaches a certain level of charge or voltage. This voltage is of the same polarity as in the initial state just before t1 (albeit at a somewhat reduced level, again assuming that some loss of energy has occurred in the device between t3 and t4). The method may then end (796). Alternatively, the method or parts thereof may be repeated. In particular, the first switching device 3 may again be switched (793) to a conducting or "ON" state, etc. Capacitor 1 may again be charged (792), in particular to its initial charge state, for example to compensate for the dissipation of electrical energy in the device.

[0392] 37 and the above description, the delay between t2 and t3 may be specifically selected by the user or manufacturer to allow capacitor 1 to be recharged. To this end, the control unit 544 may have one or more dials 545 or other user interfaces such as a touch screen 546.

[0393] FIG. 33 shows in schematic form an apparatus for generating a magnetic field according to an embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 32. However, the second branch 6 of the circuit shown in FIG. 33 does not include a switching device 703, but instead has a diode 4 (or other electrical component or assembly of electrical components that conducts or is arranged to conduct current mainly in the forward direction). As will be understood, especially from the description of FIG. 2, the diode 4 is not controlled by a controller such as the control unit 544, but rather "responds" to the voltage applied to its two terminals in the second branch 6. This means that the delay between the second time point t2 and the third time point t3 is very small, or these two times may (substantially) coincide. This also means that the (re)charging of the capacitor 1 at or around the end of the first half-pulse 720 or the beginning of the second half-pulse 730 is ideally performed in a very short interval. To achieve this, the second voltage source 707 preferably has a relatively high output power.

[0394] Fig. 33 shows a solid arrow leading to the control unit 544. This arrow is intended to represent an input to the control unit 544. For example, the voltage or other parameter prevailing in a part of the circuit shown in Fig. 33, for example the line connecting the first switching device 8 and the first branch 5, may be used as an input to the control unit 544, based on which the control unit 544 may determine when any of the switching devices 3, 8, 708 should be switched from a conducting state to a non-conducting state or vice versa.

[0395] In a variation of the circuit of either Figure 32 or Figure 33, in addition to or instead of the control unit 544, analog circuitry may be used to switch one or more, particularly all, of the switching devices 3, 8, 703, 708 from a conducting state to a non-conducting state or vice versa.

[0396] FIG. 34 shows, in schematic form, an apparatus for generating a magnetic field according to an embodiment of the present disclosure. It is similar to the embodiment shown in FIG. 32. However, the charging circuit 765 of FIG. 34 does not include a second voltage source. Instead, it has a switching arrangement 760 for selectively charging the capacitor 1 with a first and second polarity using a single voltage source 7. In the illustrated example, a bridge circuit, in particular an H-bridge circuit, is used, which includes switching devices 761 to 764. When the switching devices 761 and 763 are in a conducting state and the switching devices 762 and 764 are in a non-conducting state, the capacitor 1 can be charged with a first polarity using the voltage source 7. When the switching devices 762 and 764 are in a conducting state and the switching devices 761 and 763 are in a non-conducting state, the capacitor 1 can be charged with a second polarity opposite to the first polarity using the voltage source 7.

[0397] The switching devices 3, 703 and 761 to 764 may again be controlled by a suitable controller, such as the control unit 544, and / or by analog circuitry (not shown in FIG. 34).

[0398] The charging circuit 765 of FIG. 34 may also be used in relation to the embodiment of FIG. 33, whereby, again, it would be preferable for the voltage source 7 to have a relatively high output power so as to minimise (re)charging times at or around the end of the first half-pulse 720 or the beginning of the second half-pulse 730.

[0399] Fig. 35 shows, in schematic form, a circuit diagram of a charging circuit 765 of a device for generating a magnetic field according to one embodiment of the present disclosure. The charging circuit 765 of Fig. 35 can be used to replace the charging circuit 765 shown in Fig. 32 and Fig. 33 in the context of the embodiments shown in these figures or any of their modifications. In Fig. 35, only the charging circuit 765 and the capacitor 1 are shown, the first and second branches 5, 6 are shown only in dashed lines.

[0400] The charging circuit 765 of FIG. 35 again includes a first and a second voltage source 7, 707 and a first and a second switching device 8, 708. In addition to that, the charging circuit 765 includes an auxiliary capacitor 701 connected in series between the second switching device 708 and a common ground connection. The second voltage source 707 is connected to the two terminals of the auxiliary capacitor 701 so that the auxiliary capacitor 701 can be charged. In contrast to the charging circuit 765 of FIG. 32 and FIG. 33, the capacitor 1 of the embodiment of FIG. 35 is intended to be (re)charged (mainly) by the auxiliary capacitor 701 at or around the end of the first half-pulse 720 or the beginning of the second half-pulse 730, rather than by the second voltage source 707. The polarity of the second voltage source 707 (and therefore the polarity of the auxiliary capacitor 701 when charged by the second voltage source 707) is such that the auxiliary capacitor 701 is able to (re)charge capacitor 1 with a second polarity opposite to the first polarity (the first voltage source 7 is configured to charge capacitor 1 with the first polarity).

[0401] The operation of the switching devices 8, 708 of FIG. 35 may again be implemented as described with respect to FIGS. 32 and 33, particularly using a suitable controller or analog circuitry (not shown in FIG. 35).

[0402] When the switching device 708 is switched to the conducting state, the auxiliary capacitor 701 can charge the capacitor 1. Depending on the specifications of the auxiliary capacitor 701 and other parameters of the circuit, in particular the (parasitic) resistances in the circuit, the (re)charging of the capacitor 1 by the auxiliary capacitor 701 can potentially be faster than would be possible if the capacitor 1 were charged directly from the second voltage source 701 (without the assistance of the auxiliary capacitor 701). In this way, the (re)charging time can be shortened. Furthermore, the second voltage source 707 can charge the auxiliary capacitor 701 during and / or before the first half-pulse 720, i.e. in a period of time that may be (significantly) longer than the period of time between the first half-pulse 720 and the second half-pulse 730. This also means that the second voltage source 707 of the embodiment of FIG. 35 does not need to have a particularly high output power and yet the time to (re)charge the capacitor 1 can be shortened.

[0403] In a variation of the embodiment of Figure 35, a switching arrangement such as the bridge circuit shown in Figure 34 is used, whereby the auxiliary capacitor 701 of Figure 35 can be charged by the first voltage source 7. In this case, the second voltage source 707 is not required.

[0404] FIG. 38 shows, in schematic form, a circuit diagram of an apparatus for generating a magnetic field according to one embodiment of the present disclosure. At least some features of the circuit diagram shown in FIG. 38 are similar to those shown in FIG. 2. Therefore, the above description of the device shown in FIG. 2 applies mutatis mutandis to the circuit diagram shown in FIG. 38 and is not repeated here. Where elements shown in FIG. 38 have substantially the same function as elements shown in FIG. 2, they are given the same reference numbers as in FIG. 2. Where elements shown in FIG. 38 are generally similar to elements shown in FIG. 2 but differ, for example in terms of function or position in the circuit, they are given reference numbers as in FIG. 2 but increased by 800.

[0405] 38 includes a first series combination 870 of a first switching device 861 and a second switching device 862, where the first switching device 861 is electrically connected to the second switching device 862 at a first node 881. Similarly, the circuit includes a second series combination 871 of a third switching device 863 and a fourth switching device 864, where the third switching device 863 is electrically connected to the fourth switching device 864 at a second node 882.

[0406] The first series combination 870 is electrically connected in parallel with the second series combination 871 at a third connection point 883 and a fourth connection point 884, the first switching device 861 and the third switching device 863 are electrically connected at the third connection point 883, and the second switching device 862 and the fourth switching device 864 are electrically connected at the fourth connection point 884. In addition, a first terminal 888 of the (first) inductor 2 is electrically connected to the third connection point 883, and a second terminal 889 of the inductor 2 is electrically connected to the fourth connection point 884. The inductor 2 is intended to generate a magnetic field to be applied to body tissue.

[0407] The circuit further comprises a DC power arrangement 807 electrically connected between the first connection point 881 and the second connection point 882. The DC power arrangement 807 may include one or more DC power sources, for example batteries, solar panels or modules, or fuel cells. Such (separate) DC power sources may be connected in series or parallel (or any combination thereof) to form the DC power arrangement 807. Furthermore, different types of DC power sources may be combined, for example batteries in parallel with solar panels. In addition, although not shown in FIG. 38, additional switching devices may be used to selectively connect or disconnect any one or a subset of the individual DC power sources of the DC power arrangement 807, so that the individual DC power sources can selectively contribute towards providing electrical energy to the circuit.

[0408] The first to fourth switching devices 861 to 864 may be switched between a conducting state and a substantially non-conducting state under the control of the control unit 544, e.g., as indicated by the dashed arrows. Specific implementations of such a control unit 544 have already been described elsewhere herein. As with the other embodiments, the control of the first to fourth switching devices 861 to 864 may also be implemented by analog circuitry instead of or in addition to the control unit 544 (including a (micro)controller).

[0409] The operation of the circuit shown in Figure 38 will now be described, by way of example, with further reference to Figures 41 and 42. Figure 42 shows a flow chart illustrating a method according to one embodiment of the present disclosure. Figure 41 shows a graph in which the current (I) through inductor 2 is plotted over time (t).

[0410] The operation of the circuit of Figure 38 may be as follows: After the start of the method 890, an apparatus is presented 891 having circuitry corresponding to the circuit shown in Figure 38.

[0411] At a first time t1, the first and fourth switching devices 861, 864 are switched (892) to a conducting or "ON" state, for example under the control of a suitable controller (such as the control unit 544). At this time, the second and third switching devices 862, 863 are both in a substantially non-conducting state. A current caused by the electrical energy provided by the DC power supply arrangement 807 then starts to flow through the inductor 2 in a first current direction of current flow with respect to the inductor 2, through the first and fourth switching devices 861, 864. As a result of the current flowing through the inductor 2, a magnetic field is generated by the inductor 2. Because the DC power supply arrangement 807 provides a DC current, the current through the inductor 2 increases, at least initially, in a substantially ramp-like manner.

[0412] At a second time t2 after the first time t1, the first and fourth switching devices 861, 864 are switched (893) from a conducting state to a substantially non-conducting state (while the second and third switching devices 862, 863 both remain substantially non-conducting). Thus, the current through inductor 2 stops substantially instantaneously. Although the current through inductor 2 does not have a resonant characteristic, the current through inductor 2 from the first time t1 to the second time t2 may nevertheless be considered a (first) current pulse 820 (also referred to herein as a positive current pulse 820).

[0413] At a third time t3 after the second time t2, the second and third switching devices 862, 863 are switched (894) from a substantially non-conducting state to a conducting state (whereas the first and fourth switching devices 861, 864 are in a substantially non-conducting state). Current then starts to flow again, but this time through the second and third switching devices 862, 863. Thus, a current caused by the electrical energy provided by the DC power arrangement 807 flows through the inductor 2 in a second current direction of current flow relative to the inductor 2 (opposite to the first current direction of current flow). As a result of the current flowing through the inductor 2, a magnetic field is again generated by the inductor 2. The current again increases, at least initially, substantially in a ramp-like manner. The method is then essentially terminated (895).

[0414] However, as an optional further step, the second and third switching devices 862, 863 may be switched from the conducting state to the substantially non-conducting state at a fourth time t4 after the third time t3 (while the first and fourth switching devices 861, 864 are both still in a substantially non-conducting state). Thus, the current through the inductor 2 stops substantially instantaneously. The current through the inductor 2 between the third time t3 and the fourth time t4 may again be considered as a (second) current pulse 830 of opposite polarity (also referred to herein as a negative current pulse 830) when compared to the (first) current pulse 820.

[0415] In one variant, the third point in time t3 (substantially) coincides with the second point in time t3 such that the second negative current pulse 830 follows (substantially) immediately after the first positive current pulse 820.

[0416] The first to fourth time points t1 to t4, or the respective delays between successive ones of these time points, can be (substantially) freely selected, for example, by the user or the manufacturer. This can be done, for example, using the control unit 544. Alternatively, the delays between these time points can be implemented with analog circuits. The same is true for the delay between the end (t4) of the negative current pulse 830 and the subsequent positive current pulse 820, when the method is repeated from step 892. In any case, the delays between successive ones of these time points (t1-t2-t3-t4-t1, etc.) do not have to be the same. Furthermore, by using a circuit according to FIG. 38, it is possible to generate one or more positive current pulses 820 before generating one or more negative current pulses 830.

[0417] FIG. 39 shows, in a schematic way, an apparatus for generating a magnetic field according to an embodiment of the present disclosure. It is closely based on the embodiment shown in FIG. 38. However, an additional electric circuit element 842 is provided. The additional electric circuit element 842 may be used to protect any one or more of the first to fourth switching devices 861 to 864 or the inductor 2. In the example shown, this is illustrated only with respect to the fourth switching device 864, but a corresponding additional electric circuit element 842 can be provided in one or more of the other switching devices or inductor 2. In the example shown, the additional electric circuit element 842 is implemented as a spark gap 842, purely by way of example. The spark gap 842 is connected in parallel to the fourth switching device 864.

[0418] The function of the spark gap 842 is as follows: After the second time t2 and / or after the fourth time t4, all four switching devices 861 to 864 are in a substantially non-conducting state. However, the magnetic field generated by the inductor 2 resists its decay, which may result in a relatively high voltage between the third node 883 and the fourth node 884. Depending on the magnitude of this voltage and the specifications of the switching devices, this relatively high voltage may damage or destroy one or more of the switching devices. If the spark gap 842 is rated (i.e. becomes conductive) for a voltage U2 lower than a voltage U3 that may damage or destroy one or more of the switching devices, then the spark gap 842 can protect the respective switching device - in the illustrated example the fourth switching device 864 - from voltages higher than U2 (i.e. including voltage U3 and above). On the other hand, the spark gap 842 should not already be in a conducting state at a voltage U1 expected to occur during normal operation (so that U1 is not already in a conducting state). <U2<U3)。

[0419] Other examples of additional electrical circuit elements 842 that can be used instead of a spark gap include passive electrical circuit elements such as a transient voltage suppression diode, a Zener diode or a Shockley diode, or active electrical circuit elements such as a triode for alternating current (TRIAC) or a thyristor. When active electrical circuit elements are used, they typically require a suitable trigger circuit, as described elsewhere herein.

[0420] Although the spark gap 842 connected in parallel to the fourth switching device 864 has been described for the purpose of protecting this switching device from high voltages, it may alternatively or additionally be possible to protect one or more of the circuit elements of the apparatus from high currents, for example by connecting an additional electrical circuit element in series with the circuit element to be protected.

[0421] It should be noted that although FIG. 39 does not show a controller (such as control unit 544), such a controller or suitable alternatives already described may also be used in conjunction with the circuit of FIG.

[0422] Figure 40 shows, in schematic form, an apparatus for generating a magnetic field according to one embodiment of the present disclosure. It is closely based on the embodiment shown in Figure 38. However, the inductor 2 is not provided as an (integral) part of the apparatus. Instead, the circuit of Figure 38 (apart from the inductor 2 and its electrical connections to the rest of the circuit) is contained in a housing or cabinet 16 or the like in a manner similar to that described with reference to Figures 5, 11, 18 and 27 to 29.

[0423] The cabinet 16 is provided with two terminals 17 and 18. The terminal 17 is electrically connected to a fourth connection point 884 in the cabinet 16, while the terminal 18 is electrically connected to a third connection point 883 in the cabinet 16. Figure 40 shows the inductor 2 as an entity separate from the cabinet 16 and its contents. The inductor 2 may again be housed in a casing 13, which is attached to a conduit tube 14 (see Figure 5). The conduit tube 14 houses two cables 15 (or a cable with two strands), which are electrically connected to the first inductor 2, in particular to at least one set of turns of the inductor 2, and which may be connected to the terminals 17, 18, as shown by the dashed lines.

[0424] In further modifications, features of the embodiments shown in Figures 2 to 4, 8 to 10, 14 to 17, 21 to 23, 26 to 29, 32 to 35 and 38 to 39 or any of the modifications described herein may be combined with one another. Furthermore, any of the above embodiments or modifications may be adapted in a similar manner to those shown in and described with respect to Figures 5, 11, 18, 27 to 29 and 40 - in particular providing devices according to Figures 2 to 4, 8 to 10, 14 to 17, 21 to 23, 26 to 29, 32 to 35 and 38 to 39, but providing the devices with terminals (terminals 17 and 18) for connection with inductor 2, respectively.

[0425] In any of the above embodiments or variations, the polarity of the individual components may be reversed, so that, for example, the negative terminal of the voltage source 7 is connected to the first branch 5 and to the second branch 6 via the switching device 8. The polarity of the switching device 3, 603 can then also be reversed--or it can remain the same, in which case the two branches 5, 6 and the two inductors 2, 609 swap their functions.

[0426] Although at least one exemplary embodiment of the present invention has been described above, it should be noted that numerous variations exist. Moreover, it will be understood that the exemplary embodiments described are merely illustrative of non-limiting examples in which the present invention may be implemented, and are not intended to limit the scope, application, or configuration of the apparatus and methods described herein. Rather, the preceding description provides those skilled in the art with instructions for implementing at least one exemplary embodiment of the present invention, whereby it should be understood that various changes in the function and arrangement of the elements of the exemplary embodiment may be made without departing from the subject matter defined by the appended claims and their legal equivalents. [Explanation of symbols]

[0427] 1. Energy storage device, capacitor 2 First inductor, one set of turns 3. Switching Devices, Thyristors 4 Electrical components or electrical component assemblies, diodes 5 First branch (of a connection circuit) 6 Second branch (of a connecting circuit) 7 (First) source of electrical energy, voltage source 8 Switches, switching devices, switching circuits 9 Second Inductor 10 Bypass circuit 11 Additional inductor 12 Additional bypass circuit 13 Casing 14 Conduit Pipe 15 Cable 16 Housing, cabinet Terminals 17-19 90~95 Method Steps 101 Capacitor 102 Inductor 103 Thyristor 104 Diode 105 First Branch 106 Second Branch 107 Voltage Source 108 Switch 200 1st half pulse 210 Second half pulse 309 Second Inductor 310 Bypass circuit 311 Additional inductor 312 Additional bypass circuit 320 1st half pulse 330 Second half pulse 390~395 Method steps 401 (first) variable capacitor 420 Capacitor arrangement configuration unit 421, 423 Additional capacitor (optional: variable) 422, 424 Additional switching devices 430 1st half pulse 431 Second Half Pulse 490~495 Method steps 503 Switching Devices 540 (First) Controller 541 (Second) Controller 542 Spark Gap 543 resistor 544 Control Unit 545 Dial / Interface 546 Touchscreen / Interface 547 Processor / Memory Device 548 Detector 549 Current (half pulse) 550a~d current 551 Body parts 590~596 Method steps 603 Switching Devices, Thyristors 609 Second Inductor 613 Casing 617, 618 terminals 620 1st half pulse 630 Second half pulse 690~695 Method steps 701 Auxiliary Capacitor 703 Switching Devices, Thyristors 707 Second Voltage Source 708 Switches, switching devices 720 First half pulse (current) 730 Second half pulse (current) 732 Voltage (at capacitor) 760 Switching arrangement components, H-bridge 761 to 764 Switches, switching devices (switching arrangement configuration parts) 765 Charging circuit 790~796 Method steps 807 DC power arrangement component 820 First Pulse (Current) 830 Second Pulse (Current) 842 Additional Electrical Circuit Elements, Spark Gaps 861~864 Switches, switching devices 870 First series combination of switching devices 871 Second Series Combination of Switching Devices 881~884 Connection points 888, 889 Terminals (of inductor) 890~895 Method steps

Claims

1. 1. An apparatus for generating a magnetic field for application to body tissue, comprising: an electricity storage device for storing electrical energy; a first inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the power storage device and the first inductor, the connection circuit including at least a first branch and a second branch; a switching device forming part of the first branch, the switching device configured to electrically connect the power storage device to the first inductor such that a current caused by the electrical energy stored using the power storage device flows through the first branch and through the first inductor, thereby generating a magnetic field in the first inductor, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the first inductor; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct current primarily in a forward direction, and that forms part of the second branch such that the current flows through the second branch between the power storage device and the first inductor, the forward current flow representing a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; a second inductor forming part of either the first branch or the second branch.

2. 10. The apparatus of claim 1, further comprising a circuit for selectively bypassing or shorting the second inductor to selectively vary the inductance of a branch of which the second inductor forms a part.

3. The inductance of the second inductor is is discretely variable, and is substantially continuously variable, 3. The device according to claim 1, wherein the device is one of:

4. 3. Apparatus according to claim 1 or 2, further comprising one or more additional inductors forming part of the branches of which the second inductor forms part.

5. 5. The apparatus of claim 4, further comprising a circuit for selectively bypassing or shorting the second inductor and / or one or more of the one or more additional inductors to selectively vary the inductance of a branch of which the second inductor forms a part.

6. The inductance of the second inductor and / or the inductance of at least one of the one or more additional inductors may be is discretely variable, and is substantially continuously variable, 5. The device of claim 4, wherein the device is one of:

7. The inductance of the second inductor and / or the inductance of at least one of the one or more additional inductors may be is discretely variable, and is substantially continuously variable, 6. The device of claim 5, wherein the device is one of:

8. The inductance of the second inductor and the inductance of the one or more additional inductors may be such that the inductance of the branch of which the second inductor forms part ranges from a minimum value to a maximum value: is discretely variable, and is substantially continuously variable, is selected to be one of the minimum value corresponds to the inductance of the branch of which the second inductor forms a part when the second inductor and the additional inductor are bypassed or short-circuited; 8. The apparatus of claim 7, wherein the maximum value corresponds to the inductance of a branch of which the second inductor forms a part when the second inductor and the additional inductor are not bypassed or shorted and the inductance of the second inductor and / or at least one of the one or more additional inductors is at a maximum.

9. the first inductor comprises at least one set of turns, preferably at least one set of generally circular, hexagonal, or rectangular turns; the turns of the at least one set of turns are preferably arranged such that when the current flows through the first inductor, each turn produces a contribution towards the magnetic field, the contributions produced by each turn being superimposed in a positive manner; the first inductor is disposed in a casing connected to a conduit through which at least one cable passes for supplying power to the at least one set of windings; The device of claim 1 or 2, wherein the second inductor is not disposed within the casing.

10. 3. The apparatus of claim 1 or 2, wherein the power storage device comprises a pulse capacitor charged by a charging circuit.

11. The apparatus of claim 1 or 2, wherein the power storage device comprises a battery.

12. 1. An apparatus for generating a magnetic field for application to body tissue, comprising: an electricity storage device for storing electrical energy; a first inductor for generating a magnetic field to be applied to body tissue; a connection circuit between the power storage device and the first inductor, the connection circuit including at least a first branch and a second branch; a switching device forming part of the first branch, the switching device configured to electrically connect the power storage device to the first inductor such that a current caused by electrical energy stored using the power storage device flows through the first branch and through the first inductor, thereby generating a magnetic field in the first inductor, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the first inductor; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct current primarily in a forward direction, and that forms part of the second branch such that the current flows through the second branch between the power storage device and the first inductor, the forward current flow representing a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; the total inductance of the first branch is equal to the total inductance of the second branch; At least 1.5 times, At least twice as many At least five times At least 10 times, At least 50 times, At least 100 times, At least 500 times, At least 1000 times, At least 2000 times, At least 5000 times, At least 10,000 times , which differ by a multiple of one of the

13. 1. An apparatus for use with a first inductor to generate a magnetic field for application to body tissue, comprising: an electricity storage device for storing electrical energy; a terminal for connecting to the first inductor to generate a magnetic field for application to body tissue; a connection circuit between the power storage device and the terminal, the connection circuit having at least a first branch and a second branch; a switching device forming part of the first branch, the switching device configured to electrically connect the power storage device to the terminals such that when the first inductor is connected to the apparatus via the terminals, a current caused by electrical energy stored using the power storage device flows through the first branch and through the first inductor, thereby generating a magnetic field in the first inductor, the current flowing through the first branch representing a first current direction of current flow between the power storage device and the terminals; an electrical component or electrical assembly, preferably an electronic component or electronic assembly, that conducts or is arranged to conduct current primarily in a forward direction, and that forms part of a second branch that allows current to flow through the second branch between the power storage device and the first inductor via the terminals when the first inductor is connected to the apparatus via the terminals, the forward current flow representing a second current direction of current flow between the power storage device and the first inductor, the second current direction being opposite to the first current direction; a second inductor forming part of either the first branch or the second branch.

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