Abstract: A filter for an electric machine is disclosed. The filter has an inductor, which is a coil, and a capacitor. The coil has multiple windings, and each turn of the windings includes at least one conductor which is designed to be flat. By virtue of the flat conductor of the coil, the capacitance of the filter is thus formed in the coil itself In the process, the surface of one conductor is arranged opposite the surface of an adjacent conductor.

Abstract: The present disclosure relates to electrical windings for a dry transformer which allows construction of a compact dry transformer even in relatively high voltage classes. For this purpose, the electrical winding has multiple windings of a winding conductor wound to form a coil. The coil has been embedded into a solid insulation body. In some embodiments, a coating of an electrically conductive material, comprising a resin matrix with at least 0.05% by weight of nanoscale filler, has been applied to at least one surface of the insulation body.

Abstract: A technique capable of reducing the resistance of an inductor electrode is provided. A second conductor 6 is constituted by an undercoating layer 11 formed of a conductive paste, and a plating layer 12 formed to cover the undercoating layer 11. Therefore, the second conductor 6 constituting part of the inductor electrode 7 can be formed at a lower cost. Respective first end surfaces 8a and 9a of first and second metal pins 8 and 9 are connected to each other by the plating layer 12 of the second conductor 6 without interposition of the undercoating layer 11 thereof between them. Hence the resistance of the inductor electrode 7 can be reduced at a lower cost.

Abstract: A sensor cord construction to prevent capacitance variation is described herein. A sensor may be connected to a controller via a cord that includes a first cable and a second cable. The first cable includes first shield wires that are twisted around the first cable in a first direction, and the second cable includes second shield wires that are twisted around the second cable in a second direction that is opposite the first direction. When the cord is twisted, one of the first or second cables may provide a positive capacitance variation, while the other of the first or second cables may provide a negative capacitance variation in an amount that is directly proportional to the positive capacitance variation. Thus, the controller detects a minimum capacitance variation, when the cord is twisted, due to the capacitance variation of the first cable and the second cable canceling each other out.

Abstract: A feedthrough includes a flange comprising an inner cylindrical surface and a planar mounting surface. The inner cylindrical surface defines a cylindrical passage within the flange. The feedthrough further includes a printed circuit board (“PCB”) mounted on the planar mounting surface of the flange, and an electrically conductive element that extends through the cylindrical passage of the flange.

Abstract: A power over Ethernet (PoE) interface for 10GBase-T Ethernet includes at least one communication channel Ethernet interface including an autotransformer having a center tap for coupling direct current (DC) power. A combination of the geometry of the toroid core of the autotransformer and in some embodiments of a common mode choke, as well as the wire twisting, the wire distribution and the wire routing allow maximizing bandwidth up to or greater than 500 MHz for 10GBase-T performance by increasing the coupling and reducing capacitance across the wires, and results in return and insertion losses and OCL that meet anticipated standards.

Abstract: A transformer 10 comprises a bobbin 20. A cylinder portion 28 of the bobbin 20 is provided with a first winding part 35 where a first wire 37 is wound and a second winding part 36 where a second wire 38 is wound at a position different from the first winding part 35 in an axial direction. At an outer circumference of the cylinder portion 28 located between the first winding part 35 and the second winding part 36, an insulating partition collar 30 is formed. On the first winding part 35, a winding partition collar 33, separating in respective sections S1, S2, is formed. On the winding partition collar 33, at least one communication groove 33a, communicating the sections S1, S2 adjacent to each other is formed. The first wire 37 is ?-wound around the first winding part 35.

Abstract: A magnetic interface circuit for interfacing between a cable side and a circuit side of a networking communication channel. The magnetic interface circuit includes a transformer and a 3-wire common mode choke (CMC). The transformer has a first winding connected to the cable side of the channel and a second winding connected to the circuit side of the channel. Each of the first and second windings has two output ports. The 3-wire CMC has a center winding and two outer windings respectively connected to the output ports of the first or second winding. The center winding has two opposite ends both used for connecting to ground.

Abstract: Provided are a transformer cooling apparatus and a transformer assembly including the same. The transformer cooling apparatus includes a first plate on which a transformer including a magnetic member and a coil is seated, a second plate disposed on a side of the first plate, the second plate being spaced apart from the first plate, and a coolant passage in which a coolant flows, the coolant passage being defined between the first plate and the second plate.

Abstract: The invention provides an inductor assembly suitable for use in high frequency switched mode power converters, where the rate of change of voltage can exceed 109 Volts per second. The inductor is formed from a ribbon (30) of conductor wound around a magnetic core (140), and further includes electrostatic screens positioned between successive windings of the conductor to provide capacitive screening, substantially reducing high frequency voltage signals propagating from one end of the inductor to the other.

Abstract: Energy management of an electronic device using multiple electric power sources. The electric power sources may include a parasitic electric power source, a rechargeable electric power source, an intermittent electric power source, and a continuous electric power source. The electronic device further may include a power supply for receiving the electric power from the source(s) and supplying electric power to the various components of the electronic device that require power. The electronic device may include a source selector for controlling which power source supplies electric power to the power supply. Energy management of the electronic device may be configured to use a permanently exhaustible power source such as a battery only when other power sources are unavailable.

Abstract: An embodiment of a circuit is described that includes a first inductor comprising a first end and a second end, where the first end of the first inductor forms an input node of the circuit. The embodiment of the circuit further includes a second inductor comprising a first end and a second end, where the second end of the first inductor is coupled to the first end of the second inductor forming an output node of the circuit; a resistor coupled to the second end of the second inductor; and an electrostatic discharge structure coupled to the output node and configured to provide an amount of electrostatic discharge protection, where the amount of electrostatic discharge protection is based on a parasitic bridge capacitance and a load capacitance metric.

Abstract: The invention provides an aligned multilayer wound coil that is compact in size and excellent in productivity, an apparatus for manufacturing the same, an electrical equipment and a non-inductive resistance to which the aligned multilayer wound coil is applied. The aligned multilayer-wound coil comprises two or more winding layers, the winding layers being provided with insulated electric wires, respectively, wound in one direction in alignment with each other, wherein a lead wire is guided out from respective ends of the coil, on a layer-by-layer basis, and wherein the lead wire guided out from one end of the coil on a layer-by-layer basis is connected to one terminal while the lead wire guided out from the other end of the coil on a layer-by-layer basis is connected to the other terminal, and winding layer coils on a layer-by-layer basis are connected in parallel with each other in a circuit.

Abstract: A multiphase inductor assembly includes an elongate conductor assembly including a plurality of bus bars that are arranged in parallel. A plurality of magnetic core material rings (e.g., ferrite or mu metal rings) surround the conductor assembly and are distributed along a length thereof. Terminals are electrically coupled to the bus bars and disposed between spaced apart ones of the magnetic core material rings. In some embodiments, the conductor assembly, in cross-section, includes respective ones of the bus bars disposed in respective quadrants. For example, each of bus bars may have a quarter-cylinder shape and may be arranged such that the conductor assembly has a circular cross-section. In other embodiments, each of the bus bars may have a polygonal cross-section, e.g., may be formed from standard rectangular bar stock.

Abstract: A method of arranging and fabricating parallel primary and secondary coils of a wideband planar transformer is provided. The spacing and width of the coils are disposed to extend the bandwidth from DC to GHz and allow for high frequency coupling when the core permeability dramatically drops and achieves low reflected energy and low loss over a wide bandwidth. A bottom mold having a pattern of hole-pairs with conductive elements inserted vertically couples to a top mold such that a middle portion of the conductive elements spans between the top and bottom molds. Dielectric material envelopes the middle portion and a displacement feature of the mold creates a vacancy. A ferrite element is deposited to the vacancy. A second top mold spans the bottom mold and dielectric material is deposited to create a molded assembly. A deposited patterned conductive coating connects the element ends to define the transformer coils.

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: This disclosure describes designs for a digitally controlled oscillator (DCO). The DCO can overcome many of the shortcomings associated with conventional voltage controlled oscillators (VCOs), and may improve wireless communication devices. The described DCO may improve the frequency synthesis process, reduce noise in a wireless communication device, and allow for simplification of various components of the device.

Abstract: The invention discloses a transformer and a backlight apparatus. The backlight apparatus includes a power module, a lamp and a transformer. The transformer includes a bobbin, a primary winding, a secondary winding, a first conductive plate and a second conductive plate. The bobbin has a high-voltage winding region and a pin. The primary winding is coupled to the power module. The secondary winding is wound on the high-voltage winding region and one end of the secondary winding is electrically connected to the pin, which is further coupled to the lamp of the backlight apparatus. A separation plate is disposed on the high-voltage winding region. The first conductive plate is disposed in the separation plate and electrically connected to the pin. The second conductive plate is disposed in the separation plate and located corresponding to the first conductive plate. Accordingly, the first conductive plate and the second conductive plate form a capacitor.

Abstract: An inductance device comprises a magnetic core, a coil a conductor and a dielectric member. The coil is made of turns of insulated conductive wire. The conductor is distinct from the coil and is insulated from the magnetic core. The dielectric member is disposed between the conductor and the coil. The dielectric member, the conductor and the coil constitute a capacitor. The inductance device is used in, for example, a filter device or a noise filter.

Abstract: An inductor device or filter such as an electromagnetic interference (EMI) filter which includes an inductor provides cancellation of parasitic capacitance of the inductor and extends high frequency performance of the inductor or filter by using an inductor network (a special case being split windings) and including capacitors to couple signals corresponding to those which are passed by the equivalent parallel capacitance of an inductor of a network of inductors such as in a multi-phase power supply of voltage converter to another inductor terminal, ground or an inductor in the ground return path. Cancellation of parasitic capacitance is provided for differential mode and common mode windings where the windings may be either inductively coupled or not.

Abstract: The invention relates to a power converter (1) comprising a magnetic core (3) and a plurality of sub-converters each having a primary winding (17, 19) and a secondary winding. The magnetic core (3) comprises an inner leg (7) and a plurality of outer legs (5, 9), each of the outer legs (5, 9) having a gap (11, 13) formed therein. The primary winding (17) of one sub-converter is wound around an outer leg and the primary winding (19) of another sub-converter is wound around another outer leg. The primary windings (17, 19) are formed from a unitary winding (21) which is wound around the legs (5, 7, 9) in a continuous fashion. The primary windings (17, 19) are mounted on a printed circuit board (PCB) (15) and interconnects between turns of the primary windings are achieved using vias (27, 29) at the ends (23, 25) of the unitary winding. The vias may be conveniently placed in the corner sections or the PCB (15).

Abstract: A method of arranging and fabricating parallel primary and secondary coils of a wideband planar transformer is provided. The spacing and width of the coils are disposed to extend the bandwidth from DC to GHz and allow for high frequency coupling when the core permeability dramatically drops and achieves low reflected energy and low loss over a wide bandwidth. A bottom mold having a pattern of hole-pairs with conductive elements inserted vertically couples to a top mold such that a middle portion of the conductive elements spans between the top and bottom molds. Dielectric material envelopes the middle portion and a displacement feature of the mold creates a vacancy. A ferrite element is deposited to the vacancy. A second top mold spans the bottom mold and dielectric material is deposited to create a molded assembly. A deposited patterned conductive coating connects the element ends to define the transformer coils.

Abstract: A monolithic integrated inductor and a method for configuring the monolithic integrated inductor are provided. The monolithic integrated inductor includes a first coil having a first inductance value, at least one second coil connected in parallel to the first coil and having a second inductance value to form a total inductance, and lines to the first coil and to the second coil. The first coil has at least two first loops spaced at a distance with a path width. The second coil has at least two second loops spaced at the distance with the path width. The first loops form a magnetic coupling, and the second loops form a magnetic coupling.

Abstract: A symmetrical differential inductor including a first spiral conducting wire and a second spiral conducting wire is provided. The first spiral conducting wire has a first end and a second end, and the second end whirls in spiral fashion towards a central portion of a spiral structure of the first spiral conducting wire. The second spiral conducting wire and the first spiral conducting wire are interwound with each other and symmetrical to a symmetrical plane. The second spiral conducting wire has a third end and a fourth end, and the fourth end whirls in spiral fashion towards a central portion of a spiral structure of the second spiral conducting wire and is connected to the second end of the first spiral conducting wire. When the first spiral conducting wire and the second spiral conducting wire having the same distance from the substrate are staggered, they extend towards the substrate.

Abstract: An inductor structure, including a winding turn layer and a shielding layer, is provided. The winding turn layer is disposed above a substrate. The winding turn layer has a plurality of turns, in which one of the turns is grounded. The shielding layer is disposed between the winding turn layer and the substrate at the projection of the grounded turn. At least parts of the winding turn layer except the grounded turn thereof are projected onto the shielding layer. The shielding layer is coupled to the grounded turn in parallel.

Abstract: An inductor device or filter such as an electromagnetic interference (EMI) filter which includes an inductor provides cancellation of parasitic capacitance of the inductor and extends high frequency performance of the inductor or filter by using an inductor network (a special case being split windings) and including capacitors to couple signals corresponding to those which are passed by the equivalent parallel capacitance of an inductor of a network of inductors such as in a multi-phase power supply of voltage converter to another inductor terminal, ground or an inductor in the ground return path. Cancellation of parasitic capacitance is provided for differential mode and common mode windings where the windings may be either inductively coupled or not.

Abstract: In a main conductor for a capacitively controlled high-voltage winding composed of pancake coils for transformers, in which the main conductor for the load current is realized as a twisted conductor, and in which a control conductor is provided which is spatially arranged inside the twisted conductor and is electrically separated from the twisted conductor, the main conductor consists of two twisted conductors (1, 2) that are electrically separated from each other. The control conductor consists of several flat copper conductors (7) covered by an insulating sheath (7a), and the copper conductors (7) are fastened to one of the twisted conductors (1, 2).

Abstract: An induction heating coil with integrated resonant capacitor is provided, along with methods of fabrication thereof, and induction heating systems employing the same. The induction heating coil includes a cable having a first conductor and a second conductor separated by a dielectric. The resonant capacitor is defined by at least a portion of the cable's first conductor and second conductor with the dielectric disposed therebetween.

Abstract: The issue to be resolved by the present invention is to provide isolation transformers with high noise attenuation rates as well as high reliability, in the high-frequency region above a few MHz, by sufficiently suppressing the amplitudes of noise attenuation characteristic curves, which are irregular, saw-tooth shaped waves with crests and troughs of various sizes, of multi-layer, multi-winding transformers. An isolation transformer comprised by a multi-layer, multi-winding primary coil 1, a multi-layer, multi-winding secondary coil 2, and a core that forms a magnetic path between the aforementioned primary coil and the aforementioned secondary coil, functions as an isolation transformer to resolve the aforementioned issue by changing the coil layers of one or both of the coils formed by winding an insulated, covered, copper-wire 5 to a multi-layer, multi-winding coil, into which a number of short-circuit rings 4 made of conducting films are inserted and layered.

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. Capacitive displacement current between the energy transfer element input winding and energy transfer element output winding is substantially reduced by balancing the relative electrostatic fields generated between these windings and/or between the energy transfer element and electrical without any additional windings.

Abstract: A capacitive voltage transformers for distribution of the power from 10 kv high potential line, includes a insulating column with a high potential terminal, a ground terminal and capacitors C1 and C2 in series connection. The column is filled with oilless dry filler. The capacitors C1 and C2 formed by a plurality of separated metallized film capacitors respectively in series or in parallel connection. At the tapping point between the capacitors there is a leading-out terminal of the secondary voltage which is connected to an induction transformer L in parallel. The transformer includes a frame with “C” shaped iron cores and windings wound around the cores. There is an over-voltage protector P connected in parallel between the tapping point and ground. A capacitive voltage divider is integrally combined with the transformer to provide a small volume, low cost device with a savings in materials.

Abstract: An inductive element is integrally configurable within a power capacitor assembly. The inductive element includes a plurality of electrically conductive sheets electrically connected in parallel, and which sheets are rolled and formed into a generally cylindrical body. A first electrode is in electrical contact with one end of the electrically conductive sheets, and a second electrode is in electrical contact with the opposite end of the electrically conductive sheets.

Abstract: A switched-mode power supply includes at least one capacitor (9) and a transformer having a plurality of windings (12, 17). Advantageously a capacitor (9) is integrated in the transformer by way of at least one multi-layer foil winding (12). This foil winding (12) of the transformer consists of a plurality of planar conductive electrodes (1, 2, 3, 4, 5, 6) which, alternately with an insulating dielectric foil, are stacked onto each other to form an electrode stack.

Abstract: The invention concerns an air-core primary voltage winding comprising a conductive wire coil coated with an insulating sheath, characterized in that said coil (1) is encapsulated in a high voltage insulating thermoplastic resin (2), and in that it further comprises an electroconductive potential fixing surface layer (3) in thermoplastic resin compatible with the thermoplastic resin of the insulating encapsulation (2), deposited on this encapsulation.

Abstract: An inductive element is integrally configurable within a power capacitor assembly. The inductive element includes a plurality of electrically conductive sheets electrically connected in parallel, and which sheets are rolled and formed into a generally cylindrical body. A first electrode is in electrical contact with one end of the electrically conductive sheets, and a second electrode in electrical contact with the opposite end of said electrically conductive sheets.

Abstract: The invention relates to a switched-mode power supply including at least one capacitor (9) and including a transformer having a plurality of windings (12, 17). The invention has the advantage that the capacitor (9) is integrated in the transformer by means of at least one multi-layer foil winding (12) and this foil winding (12) of the transformer consists of a plurality of planar conductive electrodes (1, 2, 3, 4, 5, 6) which, alternately with an insulating dielectric foil, are stacked onto each other to form an electrode stack.

Abstract: An improved structure of a multi-slotted iron rod includes a core, a coil, and a lead frame. The core is a rod is made from good magnetic iron powder. The core has a fixture area and a winding area. The winding area has several winding sections and isolation sections. The winding area is used for coil winding. The isolation sections serve as capacitors. The fixture area has a hexagonal cross section and is used as a fixing end during winding. The coil winds on the winding sections of the core. The lead frame is attached to the two sides of the isolation sections of the core for connection to an electrical circuit. The device utilizes the above components to wind the coil on the winding sections of the core. The output pin of the coil is soldered to the lead frame of the isolation sections. The lead frame is soldered on the PC board. The capacitor of the isolation section of the core is connected in parallel to the coil in the winding section.

Abstract: Wound, solid state inductors are provided by winding flexible plastic tape having electrically insulative and magnetic permeability properties. Such tape is sometimes referred to as magnetic tape. An electrically conductive layer is placed on at least one surface of the magnetic tape, or both, and electrical connections are provided to the ends of the electrically conductive layer or layers. When the magnetic tape is wound into a coil, spirally or helically, and an alternating current is applied to the electrical connection, an inductive reactance will be noted. If there are two electrically conductive layers, and a voltage is applied between them, a capacitive reactance will be noted. In that case, a complex capacitive inductor element or inductive capacitor element has been configured. The wound inductors are small, light weight, inexpensive, and relatively shock proof, when compared with prior wound inductors having separate magnetic cones and wire windings placed over them.

Abstract: To simplify coil production, in particular coils used for high-voltage transformers, a conductor is wound on to a winding form. The conductor comprises a plurality of conductor portions. The conductor portions overlap one another partially and are insulated from one another. A conductor and a winding arrangement can be produce with this method.

Abstract: A pulse transformer for use in a high frequency motor controller to isolate the electronic control stages from the power stages in a motor controller. The primary and secondary windings are wound on a common ferrite core and spaced apart from one another. The wire size used for the windings is relatively small (gauge 37 or less). Each of the windings has between 10 and 13 turns. The interwinding capacitance must be below 5 picofarads, preferably below 1 picofarad, and most preferably below 0.2 picofarads.

Abstract: The present invention includes a method for separating AC and DC components of a composite waveform, and an inductive device capable of performing the method. The present invention also includes a ground fault condition monitoring system containing an inductive device of the present invention, and an electrical distribution system containing such a ground fault condition monitoring system, such as one for a lighting system.

Abstract: A transformer designed for 1:N voltage transformation (where 1:N may be any rational number) at high frequencies (such as over 7 megahertz) can achieve acceptable frequency response and attendant improved values of signal attenuation and signal distortion by physically separating two or more sets of electrically tightly coupled windings and connecting one winding of different sets in parallel and the other winding of the same sets in series. This interconnection of windings to achieve a 1:N transformation ratio reduces the negative effects of the interwinding capacitance thereby providing the improved frequency response.

Abstract: The present invention provides an LC noise filter consisting of a capacitance and an inductance, including a first insulation sheet having a plurality of portions folded alternately in the opposite directions and stacked one above another; a first conductor applied to the insulation sheet at one side and adapted to form a coil having a given number of turns when the folded portions of the insulation sheet are folded alternately in the opposite directions and stacked one above another; and a second conductor applied to the insulation sheet at the other side and located substantially opposite to the first conductor to form a capacitance therebetween, whereby the filter can eliminate incoming noises without creation of any undesirable phenomenon such as ringing or the like.

Abstract: The present invention reduces the volume and weight of capacitive and inductance devices, particularly used in filters, by combining the capacitive elements and inductive elements into the same construction. Accordingly, alternating conducting and dielectric sheets of material are wound into a coil. The conducting sheets can be variously connected to signal lines and to ground in order to form common mode, differential mode and/or mixed mode filters.

Abstract: A method and apparatus for suppressing capacitive current in transformers is described. The winding of a transformer is constructed or modified into two substantially identical winding halves wired in a series aiding configuration. Two leads emanate from the center point of the winding, where the two halves are connected in series. This center point is at a constant potential throughout the switching cycle of the transformer. Suppression of the capacitive current in the input/output leads of the transformer is achieved by introducing common mode impedance into each lead and a corresponding center tap lead. The common mode impedance can be introduced in a variety of ways such as: running the pair of leads through a toroid, bead or sleeve of magnetic material; winding the leads on a magnetic toroid or rod; or using the magnetic core structure to introduce the impedance.

Abstract: A line filter assembly adapted to be inserted in an electrical power supply circuit of various electronic appliances for avoiding an invasion and leakage of noise include first and second core members each having a pair of opposite arms connected together through a common bridge. Coils are formed on the arms of each of the core members in such a manner that directions of magnetic fluxes produced in the closed magnetic circuit as a result of flow of line currents counteract while the same coils are so arranged that the magnetic fluxes produced in the closed magnetic circuit as a result of the flow of the line currents are oriented in the same direction.

Abstract: A line filter arranged in such a manner that a foil conductors are used as the coil conductor and the shield plate, and a reactor is formed therein by laminating and winding the foil conductor and the shield plate with an insulating material held therebetween. A line filter arranged in such a manner that a pair of coil blocks connected to each other in parallel is provided on the iron core leg is included in the scope of the invention. Each of the coil blocks is structured in such a manner that the coil conductor and the shield plate made of the foil conductors are stacked and wound via the insulating material. A structure is included within the scope of the invention, the structure having a plurality of filter mechanisms connected to one another in series, each of the filter mechanisms being constituted by a pair of coil blocks connected to each other in parallel.

Abstract: A line filter assembly adapted to be inserted in an electrical power supply circuit of various electronic appliances for avoiding an invasion and leakage of noise includes first and second core members each having a pair of opposite arms connected together through a common bridge. Coils are formed on the arms of each of the core members in such a manner that directions of magnetic fluxes produced in the closed magnetic circuit as a result of flow of line currents counteract while the same coils are so arranged that the magnetic fluxes produced in the closed magnetic circuit as a result of the flow of the line currents are oriented in the same direction.

Abstract: A composite LC element including integrally a coil and a capacitor which comprises a layered film structure wherein insulating films and electrode sheets with terminals at their both ends are alternately laminated, said layered film structure being wound in a spiral form from its one end. An intermediate electrode sheet having a shorter length and having a terminal at its one end may be interposed between said insulating films. Said electrode sheet may have an additional terminal at an intermediate portion.

Abstract: A pulse transformer for use in a high frequency motor controller to isolate the electronic control stages from the power stages in a motor controller. The primary and secondary windings are wound on a common ferrite core and spaced apart from one another. The wire size used for the windings is relatively small (gauge 37 or less). Each of the windings has between 10 and 13 turns. The interwinding capacitance must be below 5 picofarads, preferably below 1 picofarad, and most preferably below 0.2 picofarads.