Abstract: Transformers and methods of constructing transformers are disclosed. In one embodiment, a method of constructing a transformer includes wrapping a first primary winding around a core, wrapping a secondary winding around the core, and wrapping a second primary winding around the core. The first primary winding traverses substantially an entire circumference of the core in a first circumferential direction. The secondary winding includes a first half and a second half. The first half traverses substantially the entire circumference of the core in the first circumferential direction, and the second half traverses substantially the entire circumference of the core in a second circumferential direction opposite the first circumferential direction. The second primary winding traverses substantially the entire circumference of the core in the second circumferential direction.

Abstract: Provided is a choke coil including: a first primary winding portion formed by winding a primary coil by n turns; a second primary winding portion formed by winding the primary coil by N turns; a first secondary winding portion formed by winding a secondary coil by N turns; and a second secondary winding portion formed by winding the secondary coil by n turns, wherein the n and N satisfy the condition: n?N.

Abstract: Disclosed herein are various embodiments of compact coil power transformers configured to provide high voltage isolation and high voltage breakdown performance characteristics in small packages. Compact coil transformers are provided across which power may be transmitted and received by primary and secondary coils disposed on opposing sides of a substrate without high voltage breakdowns occurring therebetween. At least portions of the compact coil transformer are formed of an electrically insulating, non-metallic, non-semiconductor, low dielectric loss material. The compact coil transformers may be formed in small packages using, by way of example, printed circuit boards, flex circuits, lead frames, CMOS and other fabrication and packaging processes.

Abstract: An audio amplifier, that includes a planar inductor structure that includes a first plurality of windings, formed on layers of a first circuit board and a second plurality of windings, formed on layers of a second circuit board. The planar inductor structure may further include a sense winding.

Abstract: A multi-coil choke for an AC power conditioner includes a magnetic core having first, second and third parallel legs. A first coil wrapped around the first leg terminates in first and second leads at respective ends. A second coil wrapped around the second leg terminates in first and second leads at respective ends. A third coil wrapped around the third leg terminates in first and second leads at respective ends. A fourth coil is formed from a proximal portion of the second lead of said first coil. The fourth coil is wrapped around a distal portion of the second lead of the third coil. A fifth coil is formed from a proximal portion of the second lead of the third coil. The fifth coil is wrapped around a distal portion of the second lead of the first coil. AC power conditioners using one or more such chokes are also disclosed.

Abstract: A wide-band balun device includes a first metallization deposited over a substrate and oriented in a first coil. The first coil extends horizontally across the substrate while maintaining a substantially flat vertical profile. A second metallization is deposited over the substrate and oriented in a second coil. The second coil is magnetically coupled to the first coil and a portion of the second coil oriented interiorly of the first coil. A third metallization is deposited over the substrate and oriented in a third coil. The third coil is magnetically coupled to the first and second coils. A first portion of the third coil is oriented interiorly of the second coil. The third coil has a balanced port connected to the third coil between second and third portions of the third coil.

Abstract: A super high power transformer of the invention includes a base, a plurality of plate bodies, and a plurality of isolating bodies. The base further includes a main core part, a plurality of opening slots, and a plurality of side wing parts. The main core part has a penetrating hole at the center thereof Each of the plate bodies has an open hole for slipping on the main core part and a guided slot that has a pole lead on both sides thereof Each of the isolating bodies has a through hole for slipping on the main core part and a guided slot. There is also a pole lead positioned on both sides of the guided slot. To be slipped on the main core part, the plurality of plate bodies and the insulating bodies are alternately stacked up with the plate bodies staggering in turning a 90-degree angle apart sequentially.

Abstract: Disclosed is an integrated electromagnetic interference filter capable of providing a leakage inductance sufficient to filter the differential mode electromagnetic interference by integrating four inductors for interference filtering in one core structure and controlling the coupling degree between the four inductors for interference filter.

Abstract: A transformer can be mounted on a circuit board. The circuit board includes a high-voltage line and a load. The transformer includes a bobbin used for winding a coil. The bobbin includes a first secondary area. A first secondary high voltage pole extends from the first secondary area. A first secondary high voltage pin is fixed on an end of the first secondary high voltage pole away from the first secondary area. The bobbin is made of an insulator. The first secondary high voltage pin is made of a conductor. The high voltage end of the coil is disposed on a top surface of the first secondary high voltage pole and electrically connected to the first secondary high voltage pin. The first secondary high voltage pole is capable of jumping across the high-voltage line to make the first secondary high voltage pin to electrically connect to the load.

Abstract: An inductor and a transformer, each of which includes a first bobbin on which a first coil is wound and a second bobbin on which a second coil is wound, are provided. The first bobbin includes a first bobbin part on which the first coil is wound and a first support part provided at one end of the first bobbin part. The second bobbin includes a second bobbin part on which the second coil is wound and a second support part provided at one end of the second bobbin part. Another end of the first bobbin part is coupled to the second support part and another end of the second bobbin part is coupled to the first support part.

Abstract: An entirely integrated EMI filter is based on a flexible multi-layer strip material. An EE or EI core comprises two side pillars and one middle pillar and forms a closed magnetic circuit. The middle pillar has an air gap. A first winding and a second winding respectively are wound around the two side pillars in a same winding direction. The middle pillar is wound with a third winding and a fourth winding, or with only a fifth winding. Passive components (e.g., all passive components) of the EMI filter are integrated into one core so that in its differential mode, insertion loss is significantly reduced, the size and volume are reduced, and the distribution constant of the EMI filter has less impact on the filter's performance.

Abstract: A divided structure energy transfer assembly for use in a flyback power converter is disclosed. An example energy transfer includes first and second magnetic cores. First and second input windings are wound around the first and second magnetic cores, respectively. The first input winding is coupled in parallel with the second input winding. First and second output windings are wound around the first and second magnetic cores, respectively. A rectified output of the first output winding is coupled in series with a rectified output of the second output winding. The first and second input windings have a first polarity and the first and second output windings have a second polarity. The first polarity is an opposite of the second polarity.

Abstract: A reactor is provided in which coil segments (5-1, 5-2) of each of first and second auxiliary winding elements (2-1, 2-2) is of a multilayered and aligned winding structure. The coil segments (5-1, 5-2) of the first auxiliary winding element (2-1) and the coil segments (5-1, 5-2) of the second auxiliary winding element (2-2) are disposed within respective space areas (6-1, 6-2) delimited between the coil segments of the second auxiliary winding element and an outside and between the outside and the coil segments of the first auxiliary winding element. The coil segments of each of those first and second auxiliary winding elements are so combined as to be adjacently alternately positioned in a line to thereby form a main winding body (3). The pair of the auxiliary winding elements are connected parallel to each other.

Abstract: A transformer (1) for balancing the current in several channels, having a primary winding (Wp) and at least two secondary windings (Ws). The transformer (1) has a plurality of closed transformer cores (2) on each of which a secondary winding (Ws) is disposed. The primary winding (Wp) encloses all transformer cores (2). The primary and the secondary windings are preferably disposed opposite each other on the transformer core (2). Current balancing is effected through changes in flux in the secondary windings (Ws) and a primary flux response.

Abstract: Multi-winding magnetic structures and methods of making multi-winding magnetic structures are disclosed. In one embodiment, a multi-winding magnetic structure includes a core constructed of a magnetic material and a plurality of windings. The core includes a core top, a core bottom, and a plurality of columns. The core top has an exterior edge defining a shape of the core top. A central section of the core top has a substantially constant thickness that defines a thickness of the core top. The core bottom is beneath the core top and has an exterior edge defining a shape of the core bottom. A central section of the core bottom has a substantially constant thickness that defines a thickness of the core bottom. The thickness of one of the core bottom and the core top decreases from an edge of its central section to its exterior edge. The plurality of columns extends from the core bottom to the core top and the plurality of windings are wound around the columns.

Abstract: A current transformer (5) having a plurality of primary and secondary windings, comprising a top housing head (10), a column (20) of insulating material mounted on a base (30) which supports said top housing head, a guide tube passing through a central passage in said column, a metal core casing (40), inside said top housing head, enclosing a plurality of cores (42) along with secondary windings, wherein said top housing head is a non metallic tank which supports a primary conductor (18) having bushing insulation layers (34) thereon and a dielectric fluid (8) fills said top housing head and said column of insulating material.

Abstract: A composite transformer includes: a transformer core including transformer-core legs; inductor cores including inductor-core legs; windings wound around the transformer-core legs and the inductor-core legs; the transformer core includes a pair of transformer bases connected to both ends of each of the transformer-core legs, and allows formation of closed magnetic circuits in the transformer core; each of the inductor cores includes one of the inductor-core legs, an outer core leg, and a pair of inductor bases connected to both ends of the one of the inductor-core legs and both ends of the outer core leg, and allows formation of a closed magnetic circuit in each inductor core; and the windings are wound in such directions that the magnetic fluxes produced in the transformer-core legs cancel each other in the closed magnetic circuits in the transformer core whichever of the windings is energized.

Abstract: A method and system of generating multipolar electromagnetic energy from bipolar electromagnetic energy, comprising supplying bipolar electromagnetic energy to plural cascades in a bipolar electromagnetic circuit such that at least a portion of said bipolar energy is converted into multipolar energy therein and separating said multipolar energy from other forms of energy produced by said circuit.

Abstract: A multi-winding inductor includes a first foil winding and a second foil winding. One end of the first foil winding extends from a first side of the core and wraps under the core to form a solder tab under the core. One end of the second foil winding extends from a second side of the core and wraps under the core to form another solder tab under the core. Respective portions of each solder tab are laterally adjacent under the magnetic core. A coupled inductor includes a magnetic core including a first and a second end magnetic element and a plurality of connecting magnetic elements disposed between and connecting the first and second end magnetic elements. A respective first and second single turn foil winding is wound at least partially around each connecting magnetic element. Each foil winding has two ends forming respective solder tabs.

Abstract: A high voltage transformer for cascade coupling wherein the high voltage transformer comprises a primary winding, a high voltage winding and a transformer core, and wherein the primary and high voltage windings encircles concentrically at least a part of the transformer core, and wherein the high voltage transformer is provided with a secondary winding, as the high voltage winding comprises one or more single layers connected in parallel.

Abstract: There is disclosed a voltage summer including a transformer having a primary side and a secondary side, wherein a first voltage to be summed is connected to the primary side and a second voltage to be summed is connected to the secondary side. There is further disclosed a transformer comprising a primary winding and a secondary winding and having a turns ratio of primary winding to secondary winding of x:y, providing x turns in series in the primary winding and providing y turns in series in the secondary winding; providing an equal number of turns in the primary and secondary windings; and closely coupling each primary winding turn with a secondary winding turn.

Abstract: The disclosure relates to a ring-shaped core for a power transformer. The ring-shaped core extends about an imaginary center axis in the form of a closed toroidal structure and is constituted of a plurality of adjacent layers of sheet metal. The ring-shaped core, along the length of the toroidal structure, is constituted of at least three core section modules that can be connected to and detached from each other, the core section modules being interconnected by an overlap of individual sheet layers and/or sheet layer sections. The disclosure also relates to the arrangement of ring-shaped cores having winding modules. The latter can be arranged in a common connecting structure and every ring core having winding modules arranged therein can be separately introduced into the connecting structure and removed therefrom in a non-destructive manner.

Abstract: The present invention provides a transformer capable of driving a plurality of lamps with one transformer by increasing the number of outer bobbins wrapping an outer circumferential surface of an inner bobbin wound by a coil and the number of output terminals by winding other coils around the outer bobbins.

Abstract: A transformer is provided with at least one core leg on which three windings are arranged side by side, whose discharges are designed to be mutually insulated. Each winding is formed by a near-core low-voltage winding, which are each wound by an associated high-voltage winding, and the discharges of the low-voltage windings are axially designed, so that the lateral spacing of the windings to each other is minimized.

Abstract: A switch comprising a plurality of transformers and a path comprising a number of wires. Each of the plurality of transformers comprises a core and a control winding. The path is configured to connect the plurality of transformers to each other. Non-direct current flows through the path. Direct current is sent into the control winding for each of a portion of the plurality of transformers to saturate the core for the each of the portion of the plurality of transformers such that a transfer of energy between the core for the each of the portion of the plurality of transformers and the path is substantially absent.

Abstract: A transformer 10 has a first core CR1, a second core CR2, a first transformer primary winding W1, a coil 45, a coil 46 and a coil 47. The second core CR2 is integrally formed with the first core CR1. The first transformer primary winding W1 is wound onto the first core CR1. The coil 45 is wound onto the first core CR1 and forms a transformer T1 together with the first transformer primary winding W1. The coil 46 is wound around the first core CR1 and forms a transformer T2 together with the first transformer primary winding W1. The coil 47 is connected to the coil 45 and coil 46 and forms an output coil using the second core CR2 as a magnetic core.

Abstract: A portable apparatus for voltage transformation is capable of temporarily augmenting a power transformer. A transformer with a first medium voltage primary winding, a second medium voltage primary winding and a low voltage secondary winding is selectably coupled to a plurality of medium voltage electrical power input couplings capable of temporarily coupling with medium voltage power on a plant. An interlocked switch selectably couples the medium voltage electrical power input couplings to the medium voltage primary windings of the transformer such that only one medium voltage primary winding of the transformer is coupled at a time to the medium voltage electrical power input couplings. The interlocked switch can use a captive key system to prevent more than one secondary winding from being simultaneously connected. Medium voltage circuit protection devices such as fuses are included.

Abstract: A programmable antenna interface for coupling an antenna to a transceiver having a receiver section and a transmitter section, includes a transformer that is adjustable in accordance with a control signal. A transmit/receive module couples the transformer to the receiver section in a receive mode and to the transmitter section in a transmit mode. The control signal controls the transformer to a first impedance in the transmit mode and controls the transformer to a second impedance in the receive mode.

Abstract: A three-phase, multi-winding includes a core, the core including a hub and an outer shell around a perimeter of the hub. wherein the hub and the outer shell are in a fixed position with respect to each other. The core also includes multiple slots. In addition to the core, the multi-winding device includes a primary winding positioned in at least two of the slots; and multiple spatially distributed secondary windings, wherein at least one of the secondary windings is positioned proximate the primary winding in at least one of the two slots.

Abstract: A neutral-grounded structure and a method for delta-connected windings are provided. The delta-connected windings include a first phase winding, a second phase winding, and a third phase winding. A grounding winding is disposed on at least one of the phase windings. The first end of the grounding winding is connected to a grounded point which is utilized as a neutral point. The second end of the grounding winding is connected to a tap of one of the other two phase windings. The voltage phase displacement between the grounding winding and the phase winding corresponding to the grounding winding is 180 degrees. According to the above-mentioned neutral-grounded structure, all the three phase-to-ground voltages are the same when the three phase voltages are balanced. Accordingly, the present invention can solve correlated problems due to differences of the three phase-to-ground voltages of delta-connected windings with conventional grounding methods.

Abstract: An isolation magnetic device produced by inserting a first end of a wire through a first hole of a core, wrapping the first end of the wire around a first side of the core and inserting the first end of the wire through a second hole of the core. The second hole of the core is spaced from the first hole and has a longitudinal axis extending parallel to a longitudinal axis of the first hole. The device is further produced by inserting a second end of the wire through the second hole of the core, wrapping the second end of the wire around the first side of the core and inserting the second end of the wire through the first hole of the core.

Abstract: The invention provides a transformer for a computer tomography gantry (91) for transfering contactlessly electrical energy from a stationary part of the gantry (92) to a rotary part of the gantry (93), wherein the transformer comprises a set of primary windings (103, 105, 203, 204), a set of secondary windings (103, 105, 203, 204), a set of first cores (101, 202, 301), a set of second cores (101, 202, 301), wherein the set of primary windings (103, 105, 203, 204) being arranged at the set of first cores (101, 202, 301) on the stationary part of the gantry (92), such that a winding of the set of primary windings (103, 105, 203, 204) is adapted to induce a magnetic flux into a core of the set of first cores (101, 202, 301), wherein the set of secondary windings (103, 105, 203, 204) being arranged at the set of second cores (101, 202, 301) on the rotary part of the gantry (93), such that a winding of the set of secondary windings (103, 105, 203, 204) is adapted to induce a magnetic flux into a core of the set of

Abstract: A magnetic element includes a magnetic core assembly and multiple winding coils. The magnetic core assembly is used for proving a closed magnetic flux path and includes a first side plate, a second side plate, a first side pillar, a second side pillar and at least two middle pillars. The first and second side pillars are arranged between the first and second side plates and respectively disposed on bilateral edges of the first and second side plates. The at least two middle pillars are arranged between the first and second side pillars and includes a first middle pillar and a second middle pillar. The winding coils are wound around the at least two middle pillars.

Abstract: A magnetic component, with a first and a second U/UR core (U1, U2) assembled to a first O-shaped core assembly, wherein an U/UR core has—according to its shape—a first post and a second post with free ends on one side and a leg connecting the first post and the second post on their other side, wherein the first and the second U/UR core (U1, U2) are assembled with their free ends abutting each other to form the first O-shaped core assembly. The free ends of a third U/UR core (U3) are abutting the outside of the first O-shaped core assembly on one side and that the free ends of a fourth U/UR core (U4) are abutting the outside of the first O-shaped core assembly on an opposite side. In another embodiment, the leg of a third U/UR core (U3) is abutting the outside of the first O-shaped core assembly, wherein the ends of a fourth U/UR core (U4) are abutting the ends of the third U/UR core (U3). In a further embodiment, the ends of a third U/UR core (U3) are abutting the outside of the first O-shaped core assembly.

Abstract: A switching power supply device includes a first series circuit of first and second switching elements connected in parallel with a DC power supply. An isolation transformer has primary and secondary windings and first and second auxiliary windings, a first layer including the primary windings between a second layer of the two auxiliary windings, and a third layer of the secondary windings. A capacitor in series with the primary windings defines a second series circuit in parallel with the second switching element. A rectifying and smoothing circuit includes a rectifying diode and a smoothing capacitor, connected to the secondary windings. First and second control circuits turn on and off the first and second switching elements based on voltages generated in the two auxiliary windings, to obtain a DC output from the rectifying and smoothing circuit, enabling an adequate auxiliary windings voltage and stable switching operation including stable zero-voltage turn-on.

Abstract: A conductor assembly of the type which, when conducting current, generates a magnetic field or in which, in the presence of a changing magnetic field, a voltage is induced. According to an exemplary embodiment a conductor is positioned along a path of variable direction relative to a reference axis. The conductor has a width measurable along an outer surface thereof and along a series of different planes transverse to the path direction. The measured conductor width varies among the different planes. In one example, the conductor path is helical, positioned about the axis between turns of helical spaces, and the conductor width varies as a function of the azimuth angle.

Abstract: A ripple reduction circuit for use in a current doubler rectifier has first and second inductors coupled via a first coupling coefficient. The first and second inductors generate a first and a second ripple current, respectively. A third inductor is coupled to the first and second inductors; and an impedance is connected in series with the third inductor, wherein the circuit generates a third ripple current opposing the combination of the first and second ripple currents generated by the first and second inductors.

Abstract: This invention relates to a power transfer device via electromagnetic interaction. this invention proposes a power transfer device, comprising: a primary coil for transferring a power, including a first primary coil and a second primary coil; a secondary coil for transferring the power with the primary coil via electromagnetic interaction; wherein the secondary coil is positioned between the first primary coil and the second primary coil, the first and the second primary coil being configured to render the directions of the magnet fields they induce across the secondary coil consistent. With the specific association and positioning of the primary coil and the secondary coil, the power can be transferred between the primary coil and the secondary coil effectively; therefore, the size of the transfer device can be reduced significantly. This invention can be used for charging device, e.g. components of lighting products, electrical charging device, etc.

Abstract: A planar transformer includes first and second windings that may be comprised of electrically conductive traces etched onto one or more printed circuit boards. The printed circuit boards may be arranged in various orientations so as to change the turns ratio of the planar transformer. In one embodiment, the printed circuit boards are substantially similar and may be electrically connected via connectors that separate the circuit boards. Insulating sleeves may be inserted between the printed circuit boards in an interleaved configuration.

Abstract: It is desired to perform assemble, disassemble, maintenance and the like, especially of a large site superconducting coil device, in a short time. The superconducting coil device includes a plurality of coil units arranged in a circle circumference to form a toroidal shape. Each of the plurality of coil units includes a cryostat and a superconducting coil stored in the cryostat, and has a first surface parallel with a radius of the circle circumference and a second surface parallel with the radius of the circle circumference and arranged in a first direction side of the circle circumference to the first surface. The first surface contacts with the second surface of a coil unit adjacent in one direction among the plurality of coil units. The second surface contacts with the first surface of a coil unit adjacent in other direction among the plurality of coil units.

Abstract: A transformer that is capable of setting any characteristics of a detection voltage of a detection winding and accurately detecting an output voltage includes a bobbin, a magnetic core, a first input winding, an output winding, a second input winding, and a detection winding. The bobbin is tubular and includes a plurality of winding regions located at its outer portion. The magnetic core is inserted in the bobbin. The first input winding is wound in a first winding region. The output winding is wound in a second winding region adjacent to the first winding region. The second input winding is wound in a third winding region adjacent to the second winding region. The detection winding is wound in the vicinity of the first input winding. The first input winding and the second input winding have different numbers of turns and are connected in series in the same winding direction.

Abstract: In various embodiments, a high frequency transformer is provided. The high frequency transformer may include a magnetic core; a primary winding; and a plurality of secondary windings; wherein the plurality of secondary windings and the primary winding are arranged separately, and each secondary winding constitutes a parasite current transformer with the primary winding.

Abstract: A high-voltage isolation transformer utilizing balun cores for transferring an alternating current signal from a first circuit to an output circuit, and a high voltage generator, such as a Cockcroft-Walton multiplier to apply a high direct current voltage bias with a high degree of voltage isolation between the first circuit and the output circuit. Multiple balun core transformers can be used in order to reduce the voltage rise between each individual transformer.

Abstract: An electrical induction device for high voltage applications, of the type comprising a magnetic core which has at least one leg and is operatively coupled to a supporting structure, at least one inner winding which is arranged around said leg and has a first rated voltage, at least one outer winding which is arranged around said at least one inner winding and has a second rated voltage; and electrically insulating means, wherein said at least one inner winding comprises a plurality of substantially concentric turns formed by a sheet of electrically conducting material which is spirally wound, and in that said electrically insulating means comprise at least one layer of electrically insulating material which is arranged between mutually facing surfaces of said concentric turns, and first shaped insulating means which edge, at least partially, at least one of the upper and lower external rims of said inner winding.

Abstract: Disclosed is a signal transmitter including a primary winding, a first and at least one second secondary winding which are arranged at a distance from the primary winding in a first direction and are in each case inductively coupled to the primary winding, and each of which has at least two series-connected winding sections, with the at least two winding sections of each of the first and second secondary windings being arranged in at least two different winding levels, and a signal transmission apparatus having a signal transmitter such as this.

Abstract: A radio frequency (RF) coil array includes a plurality of RF coil sections arranged in a superior-inferior direction. Each RF coil section includes a plurality of asymmetric saddle coil pairs configured in an overlapping arrangement in a left-right direction. The plurality of asymmetric saddle coil pairs may include three asymmetric saddle coil pairs arranged in a left-right direction. The position of the asymmetric saddle coil pairs on the left and right may be shifted in the superior-inferior direction with respect to the middle asymmetric saddle coil pair. In an alternative configuration, each RF coil section includes a first loop coil, an asymmetric saddle coil pair and a second loop coil arranged in a left-right direction.

Abstract: A transformer includes a bobbin assembly, a primary winding coil, a first secondary winding coil, a second secondary winding coil, and a magnetic core assembly. The bobbin assembly includes a primary winding part, a first secondary winding part, a second secondary winding part and a channel. A first opening is formed in a bottom surface of the bobbin assembly and communicates with the channel. The primary winding coil is wound around the primary winding part. The first secondary winding coil is wound around the first secondary winding part. The second secondary winding coil is wound around the second secondary winding part. The magnetic core assembly is partially embedded into the channel of the bobbin assembly, and includes a first magnetic part and a second magnetic part. The second magnetic part includes a first extension post, and the first extension post is inserted into the first opening of the bobbin assembly.

Abstract: A magnetic device formed with U-shaped core pieces employable in a power converter, and a method of forming the same. In one embodiment, the magnetic device includes a rectilinear core piece formed of a magnetic material, and first and second U-shaped core pieces positioned on the rectilinear core piece. The magnetic device also includes first and second conductive windings formed about the first and second U-shaped core pieces, respectively.

Abstract: A coil system for a plasmoid thruster includes a bias coil, a drive coil and field coils. The bias and drive coils are interleaved with one another as they are helically wound about a conical region. A first field coil defines a first passage at one end of the conical region, and is connected in series with the bias coil. A second field coil defines a second passage at an opposing end of the conical region, and is connected in series with the bias coil.

Abstract: A magnetic element includes a first wire, a second wire, a third wire, a fourth wire and a first single-strand wire. The first wire is disposed at a first side of the magnetic element, and has a first end and a second end. The second wire is disposed at the first side of the magnetic element, and has a third end and a fourth end. The third wire is disposed at a second side of the magnetic element, and has a fifth end and a sixth end. The fourth wire is disposed at the second side of the magnetic element, and has a seventh end an eighth end. The first single-strand wire has one terminal simultaneously connected to the second end and the fourth end.