Abstract: An electromagnet for a thermography system comprising a first elongated magnetic core spaced apart from a second elongated magnetic core; at least a first shorting bar connecting substantially at a first end of the first elongated magnetic core and a first end of the second elongated magnetic core; and at least a first excitation coil configured to conduct electrical current.

Abstract: An electrical transformer includes a first winding, called primary, at least one second winding, called secondary, switches, and a current detection system, wherein it comprises at least one metal screen having a connection point linked to a neutral potential of the primary winding or intended to be linked to an electrical ground and placed between the primary winding and the at least one secondary winding, the screen being made of an electrically conductive material having a melting point higher than that of the materials constituting the windings; in that the primary winding comprises an input intended to be linked to an external energy source, the switches are placed at the input of the primary winding so as to be able to isolate the primary winding from the external energy source and in that the current detection system is configured to detect a current at the input of the primary winding or a current at the connection point and to close or open the switches based on the detection of the current, the dete

Abstract: An embedded transformer device includes first, second, and auxiliary windings, defined in an insulating substrate by conductive vias joined together by conductive traces. The positions of the conductive vias are arranged to optimize the isolation properties of the transformer, while the conductive traces are arranged to optimize the coupling between the primary and secondary side windings. The embedded transformer device provides favourable isolation and energy transfer between input side and output side windings, in a device with a small component size.

Abstract: An illustrative integrated circuit configured for galvanically isolated signaling includes a receiver having: a detector module coupled to receive a differential signal from terminals of a transformer secondary, the detector module responsively presenting an impedance that varies based on a magnitude of the differential signal; a biasing module that converts the detector module impedance to a response signal; and a comparator module that compares the response signal to a reference signal to obtain a detection signal indicative of oscillation in the differential signal.

Abstract: A coil component includes two or more coils configuring a common mode choke coil and functions as an inductor against a normal mode AC current. A coil component includes a pot-type core formed in a box-like shape, a flat plate core, coils, and a partition core formed of a magnetic substance. The coils are accommodated inside the pot-type core and form a common mode choke coil by making the central axes thereof substantially match each other. Further, each of end portions of the coils function as outer electrodes. The partition core is provided between the coils.

Abstract: A transmission antenna includes a closed-loop core having at least two electrically-conductive windings arranged on the closed-loop core. The windings are each electrically-actuated to generate a magnetic flux along the closed-loop core in opposing directions. The transmission antenna may generate a polarized magnetic field within a plane of the closed-loop core and provide broadband transmission of a polarized signal having a relatively flat frequency response. The transmission antenna is electrically-small, and the frequency of the polarized signal is nearly independent of the size of the closed-loop core. Multiple polarized signals may be provided, each being independently and continuously controlled through actuation of the windings. The direction of the polarized signal may also be varied. Additional windings for receiving a signal may simultaneously be employed on the closed-loop core. A method for transmitting a polarized signal with the transmission antenna is also provided.

Abstract: A choke for an EMI filter is provided. The EMI filter includes a first filtering circuit and a second filtering circuit. The choke includes a magnetic core assembly and four winding coils. The magnetic core assembly includes a first magnetic core and a second magnetic core. The first winding coil and the second winding coil are directly wound around the first magnetic core. The third winding coil and the fourth winding coil are directly wound around the second magnetic core. The first winding coil is serially connected with a first positive path of the first filtering circuit. The second winding coil is serially connected with a second positive path of the second filtering circuit. The third winding coil is serially connected with a first negative path of the first filtering circuit. The fourth winding coil is serially connected with a second negative path of the second filtering circuit.

Abstract: In one embodiment of the present invention, an electromagnetic drive unit including a coil, a yoke, and an armature is disclosed. The winding of the coil is partly wound in one direction and partly in the other direction. An electromechanical switching device includes at least one input terminal and a respective output terminal and an electromagnetic drive unit adapted to limit or to break the electrical current between the at least one input terminal and the respective output terminal.

Abstract: Optimal operating techniques are disclosed for using coreless printed-circuit-board (PCB) transformers under (1) minimum input power conditions and (2) maximum energy efficiency conditions. The coreless PCB transformers should be operated at or near the ‘maximum impedance frequency’ (MIF) in order to reduce input power requirement. For maximum energy efficiency, the transformers should be at or near the “maximum efficiency frequency” (MEF) which is below the MIF. The operating principle has been confirmed by measurement and simulation. The proposed operating techniques can be applied to coreless PCB transformers in many circuits that have to meet stringent height requirements, for example to isolate the gates of power MOSFET and IGBT devices from the input power supply.

Abstract: An Inductive Power Transfer (IPT) pick-up apparatus includes a magnetically permeable core, a first coil, being wound about the core so as to be inductive coupled therewith such that a current induced in the first coil is most sensitive to a first directional component of magnetic flux and a second coil, being wound about the core so as to be inductively coupled therewith such that a current induced in the second coil is most sensitive to a second directional component of magnetic flux. The first directional component is substantially orthogonal to the second directional component.

Abstract: A transformer having high and low voltage coils mounted to legs of a core is provided. Each low voltage coil includes conductor sheeting having opposing first and second ends and opposing first and second side edges. A pair of coil bus bars is provided for each low voltage coil. Each coil bus bar has first and second portions, wherein the first portion has a width that is more than one and a half times greater than a width of the second portion. Each coil bus bar is secured to the conductor sheeting of its low voltage coil such that the first portion of the coil bus bar is disposed at the first side edge of the conductor sheeting and the second portion of the coil bus bar is disposed at the second side edge of the conductor sheeting.

Abstract: Three-phase AC or two-phase DC choke arrangement of a frequency converter, in which is a magnetic core, in which are the phase-specific pillars of the AC choke arrangement or the branch-specific pillars of the DC choke arrangement (1a, 1b), around which are arranged the phase-specific windings of the AC choke arrangement or the branch-specific windings of the DC choke arrangement (Ldc1+, Ldc1?) to filter difference-mode currents, and in which an additional pillar (3) for damping common-mode currents is arranged in the magnetic core of the choke. The additional pillar (3) is arranged without the phase-specific or branch-specific windings fitted around it, in which case damping of the common-mode currents is achieved by means of the common-mode impedance formed by the windings arranged around the additional pillar and around the phase-specific or the branch-specific pillars.

Abstract: A composite transformer, having first and second inductors and a transformer, includes a transformer core that has a core leg around which portions of first and second windings are wound, and a base fixing the core leg, a first inductor core that has a core leg around which a portion of the first winding is wound and a base fixing the core leg, and a second inductor core that has a core leg around which a portion of the second winding is wound and a base fixing the core leg. The first and second windings are wound in a manner that flux are cancelled with each other, and are wound around the core leg of the transformer core in a manner alternately overlapping with each other, and are wound around respective core legs of the first and second inductor cores so as to be apart from each other to suppress any interference of magnetic fluxes.

Abstract: The invention is directed to a transformer and a method of manufacturing the same. The transformer has high and low voltage coils mounted to legs of a core. Each low voltage coil includes conductor sheeting having opposing first and second ends and opposing first and second side edges. A pair of coil bus bars is provided for each low voltage coil. Each coil bus bar has first and second portions, wherein the first portion has a width that is more than one and a half times greater than a width of the second portion. Each coil bus bar is secured to the conductor sheeting of its low voltage coil such that the first portion of the coil bus bar is disposed at the first side edge of the conductor sheeting and the second portion of the coil bus bar is disposed at the second side edge of the conductor sheeting.

Abstract: A filter device reduces reflections on power lines from the motor drive to AC motors by providing a differential mode choke in series with a common mode choke both shunted by resistances tailored to the characteristic impedance of the power cable for differential mode and common mode reflections respectively. By treating both common mode based and differential mode based reflections, superior transient control and motor drive performance may be obtained.

Abstract: A transformer unit and a power converting device, which lessen the influence of noise caused by an external magnetic flux, while reducing the temperature dependency of a coupling coefficient, and which transfer signals while insulating a low-voltage and a high-voltage side electrically. Air-core type insulated transformers have a first and second winding of a primary winding as a sending side and a first and second winding of a secondary winding as a receiving side. The windings of the primary winding are connected in parallel and are wound so that the directions of magnetic fields generated by an exciting current oppose each other. The windings of the secondary winding are wound so that electromotive forces to be generated by an external magnetic flux cancel each other, and are connected in series so as to raise the electromotive forces by a signal magnetic flux generated by the primary winding.

Abstract: An electromagnetic device and a high-voltage generating device which are thin and improved in the characteristics are provided in which a magnetic core is made of a cylindrical form of a ferrite material having a higher intrinsic resistance. A winding is provided by winding a flat rectangular wire conductor in an edge-wise winding form directly on substantially the entire length of the magnetic core. As any insulator such as a coil bobbin is not needed between the flat rectangular wire conductor and the magnetic core, the winding can be decreased in the overall size or thickness thus contributing to the dimensional reduction of the electromagnetic device. Also, as its flat rectangular wire conductor is wound directly on the magnetic core, the winding can be minimized in the length and thus the overall resistance. Moreover, as there is no gap between the winding and the magnetic core, the self-inductance can be reduced while the size and the number of turns of the winding remain unchanged.

Abstract: The differences in characteristics among parts or the fluctuations of the inductance value of a coil due to temperature variation is lessened by reducing the stray capacitance components induced among the layers of wound conductor, and size reduction and cost reduction are achieved. A winding portion (30) between two flange portions (22a, 22b) is divided into a plurality of sections (30a, 30b, 30c, 30d). One layer of conductor is wound from one end to the other end in each section, and then layers of conductor are wound in the alternately reversed directions to form the multilayer winding portion (30) by solenoid winding. The conductor is preferably wound in such a way that the boundary surface between adjacent sections inclines to a flange portion, which is the winding start, and the boundary surface of an upper layer is closer to the flange portion than that of a lower layer.

Abstract: An energy transfer element having windings. In one aspect, the energy transfer element includes a first winding wound around a core, the first winding has a first end and a second end. A second winding is wound around the core. The second winding has a first end and a second end. The first winding is capacitively coupled to the second winding to provide a transfer of energy from the first winding to the second winding. A third winding is wound around the core. The third winding has a first end and a second end. The first end of the third winding is electrically coupled to the first end of the second winding. The second end of the third winding is uncoupled such that an influence of an electrostatic field to be produced by the first and second windings relative to the core are to be cancelled by an electrostatic field to be created by the third winding.

Abstract: A method of transferring energy is disclosed. In one aspect, a method includes transferring energy from a first winding wound around a transformer core to a second winding wound around the transformer core. The first and second windings capacitively coupled to electrical earth. The method further includes generating a third winding electrostatic field with a third winding wound around the transformer core and coupled to the first winding. A fourth winding electrostatic field is generated with a fourth winding wound around the transformer core and coupled to the second winding. The method also includes substantially reducing a capacitive displacement current between the first and second windings with the third and fourth electrostatic fields.

Abstract: A Winding for high voltage transformer having a predetermined number of spaced winding groups joined to form a single winding transformer, each spaced winding group being solenoid wound from a predetermined number of turns. A method of forming the winding and a transformer including the winding are also disclosed.

Abstract: An energy transfer element having an energy transfer element input winding and an energy transfer element output winding. In one aspect, the energy transfer element input winding is capacitively coupled to the energy transfer element output winding. The energy transfer element is capacitively coupled to electrical earth. One or more additional windings are introduced as part of the energy transfer element. The one or more additional windings substantially reduce capacitive displacement current between the energy transfer element input winding and energy transfer element output winding by balancing the relative electrostatic fields generated between these windings and/or between the energy transfer element and electrical earth by canceling the electrostatic fields generated by all windings within the energy transfer element relative to electrical earth through the selection of the physical position and number of turns in the additional windings.

Abstract: The present invention provides a low duty cycle, high current DC pulse type transformer with increased coupling coefficient between the primary and secondary windings by changing the proximity of the primary windings to the secondary windings through a plurality of primary windings separated by layers of secondary windings thus reducing the average distance between the primary windings and secondary windings. In addition to the increased coupling coefficient, the invention provides a reduction in electrical potential between primary windings and secondary windings through an electrical connection between the primary winding and a tap within the secondary winding.

Abstract: Toroidal transformer and inductor configurations are described that allow for greater heat transfer away from internal device components. The inventive transformer allows for higher thermal and electrical efficiency, as well as for more efficient use of expensive components, such as copper wire. In one embodiment, a toroidal transformer provides access for cooling air by forming the primary winding from a single layer of thick wire and a secondary winding of few turns such that most of the primary winding is exposed to air flow. In another embodiment, a heat sink is positioned between the core and primary windings to conduct heat away from the transformer.

Abstract: A method and apparatus for transformer bandwidth enhancement is disclosed. In one embodiment, a transformer is provided for use in a high frequency communication environment. In one configuration, the transformer is configured with one or more compensation networks to improve high frequency operation and to reduce insertion loss at all frequencies. The compensation networks may be designed, in combination with a transformer, to create an equivalent all-pass symmetric lattice network having a frequency response in the desired range. In one embodiment, the compensation networks comprise a capacitance creating device which, when cross-connected to the transformer, increases transformer bandwidth.

Abstract: A cross current control system for multiple, parallel-coupled power converters includes common mode chokes, local cross current feedback controllers, and local converter controllers. Each common mode choke is coupled to a respective power converter. Each local cross current feedback controller is configured for receiving common mode cross currents from a respective local cross current detector, calculating a resultant cross current, and generating a local feedback control signal. Each local converter controller is configured for using a respective local feedback control signal to drive the respective power converter in accordance with a coordinated switching pattern. An integral choke assembly includes a common mode choke and a differential mode choke with common and differential mode choke cores configured with at least one magnetic flux path being shared by magnetic flux generated by common mode coils and differential mode coils.

Abstract: A dual transformer design, each transformer having at least a primary winding and a secondary winding disposed on a core means, wherein the core means is circumferentially disposed about an inner housing means, and the whole structure located within an outer housing. The primary winding of one transformer of said pair of transformers is electrically coupled to the primary winding of the other in a manner such as to cause induced eddy currents from one transformer to be of a magnitude and direction so as to substantially cancel the induced eddy currents from the other transformer.

Abstract: Driving a quadrapole mass spectrometer includes obtaining an air core transformer with a primary and a secondary, matching the secondary to the mass spectrometer, and driving the primary based on first and second voltage levels. Driving of the primary is via an isolating stage that minimizes low level drive signal coupling.

Abstract: A method and apparatus for detecting a partial discharge in a voltage transformer, the transformer having a first voltage winding and a second voltage winding. A grounded electrostatic shield being operably attached to the transformer, preferably between the windings. A radio frequency current transformer is operably connected to the electrostatic shield wherein the partial discharge occurring within the voltage transformer is detected.

Abstract: In a common mode choke coil, a closed magnetic circuit core (2) is divided in parallel with its magnetic circuit, and formed by superimposing together for integration a first divided magnetic core (2a), a second divided magnetic core (2b) and a third divided magnetic core (2c) which are made of an oxide magnetic substance having the high permeability. Since the closed magnetic circuit core (2) is made of the oxide magnetic substance having the high permeability, the impedance in the low frequency band (10 kHz side) is large. Also, since the sectional area of the closed magnetic circuit core (2) (divided magnetic core) is set to be small, the permeability in the high frequency band (10 MHz side) becomes high due to the dimensional resonance phenomenon, and then the impedance also becomes large. For that reason, the noise in the wide frequency band of 10 kHz to 10 MHz can sufficiently be attenuated.

Abstract: A planar magnetic device with vertically oriented coil windings having a cross-section of a core with a torroidally-shaped winding structure taken transverse to the plane of the winding structure having two adjacent “winding windows” where the coils are present. One or more gaps in the core materials surrounding the windings store most of the energy generated by the inductor. The gap of height of at least one half the height of the winding structure is confined to the area between the winding cross-sections. Furthermore, in another aspect of the invention the gap is filled with a multi-layer structure of an alternating mono-layer of equally sized ferrite particles and a layer of synthetic resin.

Abstract: A new method and structure is provided for the simultaneous creation of inductive and capacitive components in a monolithic substrate. The invention provides a method and structure whereby a vertical spiral inductor is created on the surface of a substrate. Multiple capacitors are created inside the coils of the vertical spiral conductor. A base layer of dielectric is deposited over the surface of a semiconductor substrate, contact plugs are provided in the base layer of dielectric. Multiple layers of dielectric are deposited over the surface of the base layer, layers of coils are created in the multiple layers of dielectric. Vias are provided in the layer of dielectric to interconnect overlying coils of the spiral inductor. An etch stop layer is deposited on the surface of the upper layer of dielectric.

Abstract: A stationary induction apparatus superior in insulating ability against a surge voltage includes a coil piece on a line end side surrounded by one electrostatic shield insulating layer. The coil piece and electrostatic shield insulating layer, together with another coil piece, are surrounded by another electrostatic shield insulating layer, thus forming a successively nested configuration. Each of the electrostatic shield insulating layers includes an electrical insulating layer of pressboard and first and second conductive layers respectively located on inner and outer surface sides of the electrical insulating layer, The capacitance of each of the electrostatic shield insulating layers is adjusted to control an electrical potential distribution upon application of a surge voltage.

Abstract: An electromagnetic induction device having a flat configuration that requires a relatively small space for installation on a circuit substrate includes a flat bobbin (1T) having a length (D1) smaller than a radial size (D2) thereof has primary and secondary windings (11, 12) wound thereon. This bobbin (1T) has coaxially aligned throughholes (20, 22) defined therein into which core legs (24T and 24T) of generally T-shaped first and second core pieces (23T, 23T) are inserted from opposite directions, respectively. Respective core arms (25T, 25T) of the first and second core pieces (23T, 23T) extend parallel to each other.

Abstract: A combinational inductor, which can be constructed on a surface of a semiconductor substrate or an isolator, is provided. The combinational inductor includes several spiral inductors which are connected together in series. The spiral inductors can be constructed on the same layer to produce a combinational inductor structure, because of the same metalization process used. In another aspect, connecting methods between neighboring spiral conductors include forward cascade and reverse cascade. A spiral conductor has at least one neighboring spiral conductor which is connected with it in reverse cascade. The inductance per unit square measurement of the inductor in series can be significantly increased through the connections between neighboring spiral conductors either in forward cascade or reverse cascade.

Abstract: A variable resonance descaling decalcifier device for the treatment of hard, very hard and low hardness water is provided. The device works effectively and efficiently for line frequencies in the range between 30 hertz and 400 hertz. The device includes a resonator portion and a transformer portion. The resonator portion includes four coils (L.sub.1, L.sub.2-1, L.sub.2-2, L.sub.3) which surround a pipe (T) which carries the water to be treated. The transformer portion also includes four coils (P.sub.1, P.sub.2, S.sub.1, S.sub.2), wherein the two primary windings (P.sub.1, P.sub.2) are wound in opposite directions to one another and are connected to subtract their potential differential and the two secondary windings (S.sub.1, S.sub.2) are wound in the same manner but in opposition to the phase of the primary windings. In this way, enhanced tuning with the resonator portion of the decalcifier is achieved.

Abstract: An EMI preventive AC line filter includes rack having a rectangular top open chamber and two substantially U-shaped support arms at two opposite ends of the top open chamber, a cylindrical winding holder formed of two symmetrical halves and mounted in the top open chamber of the rack, the winding holder having an axially extended cylindrical coupling groove at the center, and an iron core coupled to the winding holder and secured to the rack to hold the winding holder in place, the iron core having a U-shaped peripheral wall forced into engagement with the U-shaped support arms of the rack, and a cylindrical shaft connected between two parallel side wall portions of the U-shaped peripheral wall and received in the axially extended cylindrical coupling groove in the winding holder.

Abstract: A transformer, particularly for a voltage converter, has a primary winding having a predeterminable leakage inductance and at least one secondary winding magnetically coupled to the primary winding with a predetermined voltage-transformation ratio. The (primary) leakage inductance is increased as compared with a conventional transformer without violating the limits for implementing an appropriately functioning transformer, and without choosing an additional coil or a larger core than is required for the power transformation, in that the primary winding comprises at least two winding sections whose magnetic couplings to the at least one secondary winding are implemented such that they operate in mutually opposite senses and are arranged such that they are at least substantially magnetically decoupled from one another.

Abstract: In the vehicle-lamp lighting-on device, a body case has a connection opening formed in the front end thereof. A lighting-on transformer is disposed within the body case. The transformer includes a core housing with an iron core and a coil bobbin with a secondary coil wound thereon. The connection opening of the body case is shielded at the front end of the lighting-on transformer. A socket for receiving a vehicle discharge lamp includes a high-voltage terminal and low-voltage terminals. When the socket is inserted into the connection opening of the body case, the high-voltage terminal of the socket is connected to the high-voltage side terminal of the lighting-on transformer, and the low-voltage terminals are connected to the low-voltage side terminals. The connection opening of the body case is shielded by the front surface (made of insulating material) of the lighting-on transformer.

Abstract: Various embodiments of on chip-transformers constructed in separate metal layers in an insulator that serves as a dielectric which is formed on a substrate such as a silicon substrate. Windings with currents flowing in a first direction are constructed in a first metal layer and windings with currents flowing a second direction are constructed in a second metal layer. Windings in the first metal layer are connected to windings in the second metal layer by connectors such as vias. The transformer can be constructed in a balun layout, an autotransformer layout, a layout with the secondary separated from the primary, a layout with the secondary separated the primary and rotated with respect to an axis of the primary, a layout in which the transformer is a two stage transformer and with the first stage constructed orthogonal to the second stage, or a transformer in which the windings are constructed in a toroidal layout.

Abstract: The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.

Abstract: Two vertical, parallel, horizontally spaced signal coils are connected in series but in opposite phase across an a.c. source. Thus a buried conductor located centrally beneath the coils experiences an alternating magnetic field whose strength is due to the addition of the fields induced by the two coils. The field strength may be further enhanced by one or more of: providing a ferromagnetic flux diverter between the upper ends of the coils; placing a conductive nonmagnetic screen between them; connecting a tuning capacitor in parallel with the coils; or providing a tuning circuit having series-connected secondary coils which are flux-linked to respective signal coils and are in parallel with a capacitor. There may be a switch arrangement for switching the signal coils to in-phase connection, for use when they are oriented horizontally.

Abstract: A transformer to achieve a precise amplitude for the operating voltages produced by the auxiliary windings, and such that the construction and production of the transformer are simplified. An auxiliary winding is split into a plurality of winding elements disposed in different chambers of a chamber-type coil former. One of the chambers is disposed in the region of the air gap of a U/I core or of a U/U core, the two U-core halves having parallel limbs of different lengths.

Abstract: A two-winding, integrated-magnetic EMI filter provides damped common-mode and differential-mode inductances. The preferred embodiment of the filter has a magnetic core structure that incorporates a high-permeability C-core, a high-permeability I-core, and a low-permeability, lossy shunt. The three core pieces are assembled so as to form a structure that, similar to an E-I configuration, has two winding windows. The loss in the shunt aids in dissipating noise and it diminishes the effects of unwanted parasitic resonances by providing damping for the differential-mode inductance. Damping for the common-mode inductance is provided by losses in the C and I core pieces. Varying the reluctance of the shunt allows the differential-mode inductance to be adjusted separately from the common-mode inductance in order to tune the filter to remove desired noise frequencies. Another embodiment of the invention incorporates a high-permeability toroid core and a low-permeability, lossy shunt.

Abstract: A variable resonance descaling decalcifier device for the treatment of hard, very hard and low hardness water is provided. The device works effectively and efficiently for line frequencies in the range between 30 hertz and 400 hertz. The device includes a resonator portion and a transformer portion. The resonator portion includes four coils L.sub.1, L.sub.2-1, L.sub.2-2, L.sub.3) which surround a pipe (T) which carries the water to be treated. The transformer portion also includes four coils (P.sub.1, P.sub.2, S.sub.1, S.sub.2), wherein the two primary windings (P.sub.1, P.sub.2) are wound in opposite directions to one another and are connected to subtract their potential differential and the two secondary windings (S.sub.1, S.sub.2) are wound in the same manner but in opposition to the phase of the primary windings. In this way, enhanced tuning with the resonator portion of the decalcifier is achieved.

Abstract: A choke coil which functions not only to eliminate common mode noise but also to eliminate differential mode noise. A couple of coils are wound around a circular first core and a second core which is disposed inside the circular first core. The second core has a circular frame and a bridge which is laid in the frame. The first core may be easy to become magnetic saturation but is made of a material with a large magnetic permeability, and preferably a material with a relative magnetic permeability of several thousand, such as ferrite and amorphous. The second core is made of a material which is hard to become magnetic saturation, and preferably a material with a relative magnetic permeability of some scores to several hundred, such as dust core.

Abstract: An air-core transformer device for supplying a high-frequency, pulsating DC voltage on the secondary side of the transformer. The primary side of the transformer has two windings which are bifilar-wound having a mutual phase relationship of 180.degree., where the end of the first winding is connected in series with the beginning of the second winding at a common junction point. The voltage supply on the primary side is controlled by a time-set or time-variable power control signal at the beginning of the first winding and at the end of the second winding. A DC voltage is supplied to the common junction point. Two oscillatory circuits are formed on the primary side by a frequency control signal supplied over a field effect transistor, and are maintained by two capacitors C1 and C2, C1 being connected in parallel with the first winding and C2 being connected in parallel with the second primary winding.

Abstract: Main and supplemental windings are combined in a toroidal inductor to subntially nullify Lorentz Forces on the main winding and the magnetic field thereof which passes externally from the inductor.

Abstract: The internal and/or external magnetic fields of a coil are nullified to ad structurally detrimental Lorentz Forces and/or environmentally hazardous magnetic fields, in accordance with preestablished design objectives.

Abstract: Two coils 3a, 3b are wound over adjacent portions of a first magnetic core having two closed magnetic circuits and a second magnetic core. The winding directions of the two coils are set so that the magnetomotive forces generated by both coils may cancel each other in the second magnetic core. The magnetic fluxes flowing in the first magnetic core decrease the higher harmonics of an input current of the power source circuit, while the magnetic fluxes flowing in the second magnetic core 2 decrease the noise between the line and the ground. That is, the choke coil performs the function of choke coil and the function of noise filter at the same time.