163 results about "Electrode impedance" patented technology

A spinal cord stimulation (SCS) system includes multiple electrodes, multiple, independently programmable, stimulation channels within an implantable pulse generator (IPG) which channels can provide concurrent, but unique stimulation fields, permitting virtual electrodes to be realized. The SCS system includes a replenishable power source (e.g., rechargeable battery), that may be recharged using transcutaneous power transmissions between antenna coil pairs. An external charger unit, having its own rechargeable battery can be used to charge the IPG replenishable power source. A real-time clock can provide an auto-run schedule for daily stimulation. An included bi-directional telemetry link in the system informs the patient or clinician the status of the system, including the state of charge of the IPG battery. Other processing circuitry in the IPG allows electrode impedance measurements to be made. Further circuitry in the external battery charger can provide alignment detection for the coil pairs.

The EEG Processing Unit comprises a semi-rigid framework which substantially conforms to the Patient's head and supports a set of electrodes in predetermined loci on the Patient's head to ensure proper electrode placement. The EEG Processing Unit includes automated connectivity determination apparatus which can use pressure-sensitive electrode placement ensuring proper contact with Patient's scalp and also automatically verifies electrode placement via measurements of electrode impedance through automated impedance checking. Voltages generated by the electrodes are amplified and filtered before being transmitted to an analysis platform, which can be a Physician's laptop computer system, either wirelessly or via a set of tethering wires. The EEG Processing Unit includes an automatic artifacting capability which identifies when there is sufficient clean data compiled in the testing session. This process automatically eliminates muscle- or other physical-artifact-related voltages. Clean data, which represents real brain voltages as opposed to muscle- or physical-artifact-related voltages, thereby are produced.

In one embodiment, the present invention includes a test signal generator capable of producing an impedance test signal comprising of a sine wave having a known frequency. The test signal generator may include a crystal oscillator, a counter, and a lookup table. The lookup table output is applied to a digital to analog converter and is then low pass filtered using a conventional analog filter to produce a sine wave of a known frequency and voltage amplitude. The test signal flows through the electrode and combines with an electrophysiological signal to form a combined signal. A signal processor is used to isolate the combined signal into the test signal component and the electrophysiological component. The signal processor digitally low pass filters the combined signal and the output of the low pass filter is the electrophysiological signal. The signal processor then digitally bandpass filters the combined signal using a filter with a center frequency which is the same as the test frequency. The output of this filter is then used to calculate the electrode impedance.

A method and associated stimulation device for ensuring firing of an action potential in an intended physiological target activated by a stimulus pulse generated by an electrode of a non-invasive surface based stimulation device irrespective of skin-to-electrode impedance by: (i) increasing internal impedance of the stimulation device so as to widen a Chronaxie time period thereby ensuring firing of the action potential of the intended physiological target irrespective of the skin-to-electrode impedance; and/or (ii) generating a stimulation waveform that optimizes a non-zero average current (e.g., non-zero slope of the envelope of the stimulation waveform) during preferably substantially the entire current decay of the stimulus pulse.

The present invention relates to a system for measuring the impedance of a skin/electrode interface and selectively modifying the system gain of the monitoring circuit to compensate for errors introduced by variations in the skin/electrode impedance. More particularly, a simplified, low-cost method for measuring and compensating for skin/electrode impedance variations is provided. The skin/electrode impedance measuring circuit and determines a system gain correction factor which may be applied to the measured signal using a software algorithm, thereby eliminating the need to change the circuit topology with a programmable gain amplifier or programmable resistor network.

The invention discloses a battery panel ground insulation impedance detection circuit which comprises a partial pressure subcircuit and a voltage detection unit (11), wherein the partial pressure subcircuit is used for connecting between a positive electrode (PV+) of a battery panel and a negative electrode (PV-) of the battery panel. The partial pressure subcircuit comprises a first resistor (R1), a fourth resistor (R4) and a second control switch, the first resistor (R1), the fourth resistor (R4) and the second control switch are connected in series, the second control switch enables a to-be-detected electrode to be connected or disconnected with planet earth (PE) through opening and closing states, and forms a plurality of various connection combinations according to connection between the to-be-detected electrode and the planet earth, and the voltage detection unit (11) is used for sequentially outputting a plurality of sampling voltages according to each various connection combination. The partial pressure subcircuit is formed by respectively connecting resistors on a positive electrode impedance and a negative electrode impedance, the various connection combinations are formed under the control of the second control switch, the plurality of sampling voltages are output, positive electrode ground insulation impedance and negative electrode ground insulation impedance can be calculated, and the problem that when one electrode of a battery is infinite in ground impedance, ground impedance of the other electrode of the battery can not be calculated.

The invention discloses a super-capacitor electrode material based on graded flowerlike NiCo2O4. The super-capacitor electrode material is graded flowerlike NiCo2O4 which is directly grown on the nickel mesh of a conductive substrate by a hydrothermal method. The flowerlike structure prepared by the method for preparing NiCo2O4 is formed by assembling nanometer sheets, and in-situ growth on the three-dimensional nickel mesh is realized by selecting experiment conditions; the preparation process is easy to operate and products are regular in shape; because the electrode material directly grows on the conductive substrate, thereby avoiding to add a conductive agent and a binding agent, greatly reducing electrode impedance, increasing the contact action between the graded structure electrode material and the conductive substrate, and increasing osmosis of electrolyte by loosely assembling the nanometer sheets.

The invention discloses a high-efficiency class-F and inverse class-F power amplifier. A transistor, a parasitic compensation circuit, a harmonic control circuit and an output fundamental wave impedance matching circuit are included. The harmonic control circuit is located between the parasitic compensation circuit and the output fundamental wave impedance matching circuit, and the parasitic compensation circuit is located between the transistor and the harmonic control circuit. As for a fixed work frequency, the input end of the harmonic control circuit forms a second harmonic short dot and a third harmonic open-circuit dot, the harmonic control circuit is composed of three micro-strips, and the parasitic compensation circuit is composed of an L-type micro-strip structure. A parasitic component compensation function can be achieved by adjusting electric length parameters of a micro-strip in the parasitic compensation circuit, and meanwhile drain electrode impedance conditions of the class-F and inverse class-F power amplifier can be achieved. By means of the class-F and inverse class-F power amplifier, influences of the parasitic component on the harmonic control circuit can be effectively reduced, precise control of second harmonics and the third harmonics is achieved, and work efficiency of the power amplifier is improved.

A biomedical sensor system is disclosed that includes a high impedance conductive electrode having an electrode impedance of at least about 20 kΩ/sq-mil, and a dielectric material on a first side of the electrode for receiving a discharge of an electrical signal from the dielectric material responsive to the presence of a time varying signal adjacent a second side of the dielectric material that is opposite the first side.

Apparatuses and methods are provided for determining electrode impedances of a bioelectric signal-monitoring/recording system that includes an amplifier, and electrodes connected between a subject and the amplifier. An example apparatus includes: a voltage source outputting a voltage signal; a switching arrangement including an input electrically connected with the voltage source for receiving the voltage signal, an output electrically connected with the amplifier and the electrodes, and switches between the input and the output; and a controller in communication with the switches for opening and closing the switches to establish signal paths between the voltage source and the output, the controller calculating the electrode impedances relative to voltage outputs of the amplifier for each signal path.

The invention relates to the fuel cell field, aims to provide a direct liquid fuel cell using conductive polymer modified carbon based cobaltous hydroxide composite catalyst. The cell comprises a negative pole using foam nickel as matrix and a positive pole using hydrophobic processed carbon paper or carbon cloth as matrix; The negative pole is made by mixing the conductive polymer modified carbon based cobaltous hydroxide composite catalyst, water, perfluoro sulfonic group resin solution with concentration of 5wt% and anhydrous ethanol, blending into slurry, coating on foam nickel and drying in air naturally. The beneficial effects of the invention is: conductive polymer can increase electrode electrical conductivity, reduce electrode impedance, improve electrode activity, and improve the electricity generation performance of cell; the synthesized conductive polymer modified carbon based cobaltous hydroxide composite catalyst is non-Pt catalyst, has a low cost, is favorable to the popularization of fuel cell technology.

The electrode for high-voltage in-situ impedance spectroscopy measurement of the present invention and its preparation method and application belong to the technical field of in-situ measurement of electrical quantities under high-voltage conditions. The electrode consists of an aluminum oxide protective layer (3) deposited on the surface of the diamond anvil (2) and a metal film electrode (1); the metal film electrode (1) is circular in the center of the anvil surface of the diamond anvil (2), Copper wire (5) is bonded to the metal film electrode (1) on the side of the diamond anvil (2); the metal spacer (4) is used as another electrode, forming an axisymmetric electrode together with the metal film electrode (1) system. Electrodes are prepared by magnetron sputtering, molybdenum coating, aluminum oxide deposition, photolithography and chemical corrosion. The invention solves the problems of electrode fixing and sample cavity insulation, and can ignore the influence of the parasitic capacitance and inductance of the system on the measurement results, making it possible to measure the material impedance spectrum in situ with the diamond anvil under high pressure.

The invention discloses an anti-overflow control system. An anti-overflow detecting support is arranged on a pot cover. When soup is boiled and bubbles overflow to a detecting electrode, the impedance of the anti-overflow electrode on the anti-overflow detecting support is changed, and the temperature of the environment in a pot is detected while the impedance is detected through a wireless radio frequency reader; meanwhile, temperature information and electrode impedance information are outputted to a cooking utensil control device to be judged, the cooking utensil control device then adjusts the heat power of a cooking utensil according to the judgment information so as to prevent soup from overflowing out of the pot, and then the anti-overflow effect is achieved.

The invention relates to a wearable bio-electricity signal collection device which is extensively applied to bioelectricity recording, measuring and stimulating, especially applicable to non-gel bio-electricity measurement. The collection device is formed by the connection of electrode support components; electrode support component comprises connecting belts and fixed pieces, wherein electrode mounting holes are formed in the middle of the fixed pieces, troughs for fixing the connecting belts are formed in the sides of the fixed pieces, and at least a pair of troughs in two are symmetrically formed in the two sides of each electrode mounting holes; the fixed pieces are fixed on one ends or two ends or middle parts of the connecting belt through the troughs in the fixed pieces, the connecting belts are elastic flat belts, and the fixed pieces are rigid flat blocks. The collection device provided by the invention has the advantages of being reasonable in structure, high in degree of fitness between the electrode support component and the skin, stable in electrode impedance, high in measurement precision, comfortable to wear, detachable in electrode, convenient to adjust the position and amount of electrodes, and the electrode is in well contact with the skin.

An exemplary method includes a sound processing unit 1) directing an implantable cochlear stimulator to apply a plurality of stimulation pulses each having a first pulse width by way of a plurality of electrodes during a first stimulation frame, the plurality of electrodes including a first electrode and a set of remaining electrodes, 2) detecting a change in impedance of the first electrode, 3) adjusting, in response to the change in impedance of the first electrode, a pulse width parameter associated with the first electrode to define a second pulse width, and 4) directing the implantable cochlear stimulator to apply a stimulation pulse having the second pulse width by way of the first electrode and a plurality of stimulation pulses having the first pulse width by way of the set of remaining electrodes during a second stimulation frame subsequent to the first stimulation frame.