11994 results about "Alternate current" patented technology

The invention comprises use of Dynamically Switchable Bypass (DSB) elements in association with one or more Light Emitting Diodes (LEDs) in arrays for illumination circuits to provide rugged, reliable lighting. The DSBs are selected from Transient Voltage Suppressors, including Silicon, Metal Oxide Varistors, and Multi Layer Varistors as well as Zener Diodes. The DSBs are not used as circuit protecting devices, but rather as alternative paths for electric current to bypass failed LEDs. Bi-directional TVSs are used as alternative electric paths for circuits using Alternating Current (AC) and parallel LED arrays that light on both phases of AC. Zener Diodes are used in parallel to, but in the opposite polarity orientation to, one or more LEDs in DC or rectified AC circuits. The inventive paired DSB/LED elements overcomes the black-out problems of prior series LED illumination systems, making possible the use of robust LEDs in illumination systems where reliability, long life, low power consumption, low heat output, resistance to shock, vibration, and humidity, and self-diagnosis are important. The DSB elements have breakdown voltages slightly higher than the LED(s) they support, so that when an LED fails, the conduction through the DSB begins. Because the conduction voltage of the DSB so nearly matches the conduction voltage of the LED(s), the remainder of the circuit continues to function as normal. The system is self-diagnostic in that any LED failure presents itself as a dark LED rather than as a whole string of dark LEDs. DSBs may be used with incandescent bulbs.

The present invention takes the form of a current limiting apparatus and method for limiting current flow, induced when the level of an external signal is greater than an external signal threshold signal level, in a conductive loop formed by a medical device implanted within a living organism having electrically excitable tissue. The system includes an implantable pulse generator (IPG) system having a housing, a signal generator disposed in the housing that generates an electrical signal, and at least one lead extending from the housing to convey electrical signal to the patient. To limit the induced current flow, the IPG includes current limiting componentry, an impedance increasing element, and/or alternating current blocking elements. These components provide an alternating current impedance path to the electrical ground from a lead coupled to the capacitive element. Also disclosed are techniques for reducing the effective surface area of the current inducing loop caused by the IPG system.

An improved electrosurgical instrument and method is disclosed for simplifying making incisions and other treatments using electrosurgery. The electrosurgical instrument comprises a body having more than two electrodes with at least two electrodes having alternating current power supplied to them such that they comprise a bipolar alternating current configuration and employ a means other than electrode spacing, composition, or geometry for reducing or preventing accumulation of eschar that would otherwise form a short circuit current path and interfere with obtaining a predetermined surgical effect. In one aspect, such means for reducing or preventing eschar accumulation consists of at least one other electrode having a direct current voltage between it and at least one of the two electrodes forming the alternating current bipolar configuration. In another aspect of the invention two or more pairs of alternating current electrodes comprising bipolar electrodes are powered with alternating current having a nonzero RMS voltage sufficient to at least reduce eschar accumulations on one electrode or induce electrolysis of at least one component of a medium surrounding at least one pair of bipolar electrodes. The electrodes are separated from each other using electrically insulating materials such that electric current does not flow between at least two of the bipolar alternating current electrodes unless they contact at least one other electrically conductive medium, such as patient tissue or a medium comprising at least in part a solid, liquid, gas, or ionized component that allows electric current to flow between electrodes. In the aspect where at least one electrode is powered by direct current the electrodes are configured such that electrical current does not flow between at least one of the bipolar alternating current electrodes and at least one of the direct current electrodes unless one or more media, such as patient tissue or a medium comprising at least in part a solid, liquid, gas, or ionized component that allows electric current to flow between electrodes, are contacting or adjacent to the electrodes having a direct current voltage difference between them. The assembly comprised of the electrodes and the separating insulating materials may also employ one or more means to reduce the current flowing between them that does not produce a desired predetermined surgical effect with one aspect of such means being using an outer insulating coating configured such that one or more portions of at least one of the bipolar alternating current electrodes are insulated while leaving exposed other portions of such insulated electrodes so that they are capable of being in electrical communication with tissue or at least one material in electrical communication with tissue.

A driver circuit 3 feeds a pulse signal to an SSR 2 every half wave of alternating-current power from a commercial power source 4, and thereby separately controls the amounts of emitted light of LED groups 1x and 1y forming an LED unit 1, the LED groups 1x and 1y being connected in parallel in such a way as to point in different directions. That is, a first pulse signal for controlling the duration of light emission of the LED group 1x and a second pulse signal for controlling the duration of light emission of the LED group 1y are fed to the SSR 2 from the driver circuit 3.

A single cup pod beverage brewer is presented utilizing a pod (20) containing coffee grounds or tea leaves surrounded by filter paper. A pod holding chamber (22) consisting of a upper head (26) and a lower head (28) having an ejection disc (42). An upper head mounting frame (48) is attached to its horizontal base (50) and includes lower head rotating arms (60) attached to a first shaft (62) with a first gear motor (66) rotating the arms into a pod loading position, a pod brewing position and a pod disposal position. A second gear motor (66a) is secured to the upper head mounting frame, driving a cam (76) through a second shaft (62a) engaging the upper head to lower, seal and raise said upper head. A pod ejector solenoid (84) is disposed on the base electromechanically propelling the pod from the chamber when the lower head in the pod disposal position. An electronic control system employs a solid state direct current arrangement for control regulation and alternating current for heating system functions. An enclosure with panels and a door (90) protects moving elements and electrical controls.

A medical device assembly for cutting body tissue by means of electrotomy, includes a generator for a high frequency alternating current which can be delivered by way of a pole and an opposite pole, wherein each pole is connected to at least one respective output terminal of the generator; a gripping instrument with two gripping arms which each have at least one respective gripping surface and which are connected together in such a way that the gripping surfaces are movable towards each other, wherein the gripping surface is at least partially electrically conductive and each is individually electrically connected to a respective terminal or they are electrically connected to a common terminal for an electrical supply line; and a cutting instrument which has a handle and a cutting electrode, wherein in operation the cutting electrode is connected to a pole of the generator and both gripping surfaces are connected to the opposite pole of the generator.

An implantable medical device assembly that contains magnetic material with a saturation magnetization of at least about 0.15 Tesla and which has a direct current permeability at a static magnetic field value of 1.5 Tesla of at least 1.1. When the magnetic material and is simultaneously subjected to an alternating current electromagnetic field with a frequency of 64 megahertz and a static magnetic field of 1.5 Tesla, it has a magnetization of less than 100 electromagnetic units per cubic centimeter.

The invention provides a compensation method of direct current (DC) voltage fluctuation of a photovoltaic grid-connected inverter, and the method can be used for improving the quality of the grid-connected current through compensating an input DC side secondary pulse voltage by adding a DC voltage pulse compensation module in a DC/AC (direction current/alternating current) high-frequency link, and eliminating a grid-connected current harmonic wave caused by the DC voltage pulse. The control performance of the system can be improved without adding a filter device and adding any extra appliance.

Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, utilizing pulsations of the brachial artery contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm proximate the brachial artery and two or more spaced apart voltage sensing electrodes positioned on the patient's arm proximate the brachial artery. The voltage sensing electrodes are positioned between the alternating current flow electrodes on the arm. An alternating current source is electrically connected to the alternating current flow electrodes and a voltmeter electrically is connected to the voltage sensing electrodes. A data input device is provided along with a processing unit in communication with the data input device, the alternating current source, alternating current flow electrodes, the voltmeter, and voltage sensing electrodes. The processing unit is capable of using data from the data input device and voltage sensing electrodes to calculate the stroke volume of the patient.

In electrically stimulating neural tissue it is important to prevent over stimulation and unbalanced stimulation which would cause damage to the neural tissue, the electrode, or both. It is critical that neural tissue in not subjected to any direct current or alternating current above a safe threshold. Further, it is important to identify defective electrodes as continued use may result in neural and further electrode damage. The present invention presents system and stimulator control mechanisms to prevent damage to neural tissue.

An electrosurgical instrument blade includes a body having more than two electrodes with at least two electrodes having alternating current power supplied to them provide a bipolar alternating current configuration and employ a means other than electrode spacing for reducing or preventing accumulation of eschar. The electrodes are separated from each other using electrically insulating materials such that electric current does not flow between at least two of the bipolar alternating current electrodes unless they contact at least one other electrically conductive medium, such as patient tissue. The conductor edge portion and insulation layer each have geometric shapes and composition to reduce or eliminate the production of smoke and eschar and reduce tissue damage. The outer profile of the insulation layer and conductive element are configured to facilitate the flow of electrosurgical decomposition products away from the conductor edge where they are formed.

The present invention provides devices and systems, as well as methods, of electric field delivery and non-thermal or mild hyperthermia, and preferential or selective ablation of cancerous cells of target tissue regions. A method can include, for example, advancing a probe comprising a plurality of electrodes to a target tissue region comprising cancerous cells, and deploying the plurality of electrodes from a distal portion of a probe, and applying an alternating current so as to provide one or more electric fields extending through the volume and selectively or preferentially destroy cancerous cells within the volume.

An iontophoretic method for transporting compounds of interest across a body tissue is provided. The method utilizes an AC signal in conjunction with a barrier-modifying agent such as a fatty acid, fatty alcohol, bile acid, surfactant, or the like. The method enables the maintenance of a substantially constant electrical state in a localized region of the tissue through which transport occurs, thereby allowing a compound of interest to be transported across the tissue in a controlled and predictable manner. The barrier-modifying agent reduces the time as well as the voltage level required to achieve a target electrical resistance, thereby reducing patient discomfort and increasing the battery life of the iontophoresis device.

An aerosol delivery device is provided that includes a substrate configured to carry an aerosol precursor composition, and a resonant transformer including a transmitter coupling device and a resonant receiver coupling device that is positioned in proximity to the substrate. The aerosol delivery device also includes a pulse width modulation (PWM) inverter configured to drive the resonant transformer. The PWM inverter includes a bridge circuit coupled to the transmitter coupling device, and a PWM controller embodied as an integrated circuit and configured to output a PWM signal to the bridge circuit configured to drive the transmitter coupling device to generate an oscillating magnetic field and induce an alternating voltage in the resonant receiver coupling device when exposed to the oscillating magnetic field. The alternating voltage causes the resonant receiver coupling device to generate heat and thereby vaporize components of the aerosol precursor composition.

The invention discloses an alternating current and direct current hybrid micro-grid system and a control strategy of the micro-grid system. The micro-grid system comprises multiple generation units, load, a distribution line for connecting the generation units and the loads, and a monitoring protection unit; each generation unit comprises a large power grid, grid-connected AC/DC (alternating current/direct current) of the large power grid, an energy storage system, a DC/DC (direct current/direct current) converter of the energy storage system, a wind power generation system, an AC/DC converter of the wind power generation system, a photovoltaic power generation system, a DC/DC converter of the photovoltaic power generation system, and a diesel generator; said load includes AC non-significant load, AC significant load, AC/DC load, DC significant load and DC non-significant load; the distribution line comprises a DC distribution line and an AC distribution line; the operating status of each energy conversion device can be monitored in real time by the monitoring protection unit, two operating ways such as grid connection and isolation of the system can be realized by different control strategies, the distributive generation unit and the energy storage unit realize coordination and cooperation by controlling energy storage DC/DC, photovoltaic DC/DC, and wind power AC/DC, so that the power supply reliability is improved and the significant load can continuously operate.

Electrical energy is transcutaneously transmitted from an external charger to an implanted medical device. The external charger includes a charging head comprising a plurality of pivotable hinged sections for selectively shaping the charging head to conform to a surface of a patient. The external charger further includes an alternating current (AC) charging coil housed in the charging head for transcutaneously transmitting electrical energy to the implanted medical device. The charging head may also include one or more sensors for determining the shape of a charging coil in the charging head, which cause the charge of the coil to be adjusted based on the coil shape.

An electroimpedance tomograph with a plurality of electrodes (1) is provided, which can be placed on the body of a patient and are connected via a selector switch (60) with a control and evaluating unit (20). The control and evaluating unit (20) cooperates with the selector switch (60) such that two electrodes each are supplied with an alternating current from an AC power source (22) and the detected analog voltage signals of the other electrodes are processed in order to reconstruct therefrom the impedance distribution of the body in the plane of the electrodes, wherein a symmetrical AC power source is used to reduce common-mode signals. To further suppress interferences due to common-mode signals, provisions are made for the control and evaluating unit (20) to be set up, furthermore, for detuning the common-mode signal of the alternating current on the body against the ground by means of a common-mode signal measuring electrode (4) and, based on this, the symmetry of the symmetrical AC power source such that the common-mode signal on the body is minimized, and the corresponding detuning parameters are stored for each electrode pair.

Disclosed is an edema measuring method comprising the steps of: putting at least two pairs of electrodes on different locations selected in the body; making an alternating current to flow in the body via one pair of electrodes; measuring voltage appearing between the other pair of electrodes; calculating impedance on the basis of the supplied alternating current and the measured voltage; and calculating an index value representing the degree of edema on the basis of the impedance. Also, an apparatus using the method is disclosed.