Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.

Abstract: The invention relates to a high-voltage transformer consisting of conventional elements disposed in two different groups, namely positive voltage elements (1-5) and negative voltage elements (1′-5′), both types of elements being separated by a single insulating barrier (6). One of the ends of all elements has a ground level or “zero voltage” increasing progressively towards the other end in the positive voltage elements and decreasing progressively in the negative voltage elements in such a way that the elements in each group have equipotential voltages at the same level or distance from the ground level. Said structure eliminates parasitic capacitances and makes it possible to mount the elements very close to each other thereby considerably reducing size and consequently costs.

Abstract: A transformer (90) includes taps (96a, 96b, 96c) by which electrical contact can be made to a winding (90) of the transformer (90) at locations along its length between its end terminals. A first section (90a) of the winding (90) has a first resistance R1 (R). A second section (90a+90b) of the winding (90) has a second resistance R2 (R+3R). One or both of the first (90a) and second (90a+90b) sections can be a multilayer section. The sections are configured so that one of the ratio R1:R2 (1:4) and the ratio R2:R1 (4:1) is substantially identical to the ratio 1:n (1:4) of the windings (90a, 90a+90b). A first switch (94) permits contact to be made selectively to a selected one of the taps (96a, 96b, 96c). An amplifier (98) has an inverting (−) input terminal, a non-inverting (+) input terminal and an output terminal. One (+) of the + and − input terminals is coupled to one of the terminals (end terminal of winding 90a) of the winding (90).

Abstract: Each coil of a transformer is partitioned into two or more parallel segments. The multiple segments of each coil are interleaved with each other to form a coplanar interleaved transformer that has a greater coupling efficiency than a non-segmented coplanar interleaved transformer. In a preferred embodiment, the multiple segments are of reduced width, so that the interleaved coils consume substantially the same area as the non-segmented coplanar interleaved transformer, thereby maintaining the same inductance as the non-segmented transformer. To provide for maximum efficiency, each segment of each coil is embodied so as to have substantially equal length as each other segment of the coil.

Abstract: The invention relates to an arrangement of two cascaded transformers, i.e. an impedance transformer (24) and a balance-unbalance transformer, also referred to as balun transformer (26). A relatively simple, inexpensive, small and efficient construction of this arrangement is achieved by mounting both transformers (24, 26) on a single core (50) of a magnetic material. The arrangement according to the invention can be used in CATV networks, more specifically in CATV modules and optical receivers for use in such CATV networks.

Abstract: Multiple parallel conductor for an electrical machine and process. The conductor includes a plurality of adjacent subconductors combined to form a subconductor bundle having an outer surface with a plurality of contiguous surface sections arranged in a longitudinal direction, and a flat protective insulation covering at least one of the plurality of surface sections. At least one of the plurality of surface sections remains uncovered by the flat protective insulation covering. A mesh sheathing further covers the plurality of surface sections.

Abstract: The present invention relates to cores and coils for electrical transformers in which lateral walls of either Wescore or toroidal type cores are manufactured by winding strips of different heights or only one strip whose width reduces gradually, so that the lateral walls form an angle relative to the core upper wall. The corresponding coil is manufactured following the core pattern, on which core the coil will be placed or wound. The use of the cores and coils of the present invention achieves substantial savings in materials used to manufacture electrical transformers, while the resulting characteristics and electrical losses are improved, with load and with no-load.

Abstract: A power supply transformer for telephone to be incorporated in an AC adapter as a power supply for a telephone. A bobbin used in a power supply transformer for a telephone is configured by taking insulation as well as an insulation distance into consideration and is partitioned into three winding frames with a plurality of flanges to configure. A primary side input coil, which is connected with a power supply for commercial use, is coiled at the coil portion of the bobbin, a secondary side output coil is coiled for charging at another coil portion, and a secondary side output coil is coiled for a telephone line at still another coil portion are deemed to serve for improvement in insulation and reservation of insulation distance mutually between the respective coils.

Abstract: The presented invention concerns a coil formed by windings of a first electrical wire and windings of at least one more electrical wire whereby the wires are connected with each other at their respective ends. The starting points of the individual windings of the first electrical wire and of at least one more electrical wire are shifted against each other along the circumference of the coil body. Each wire forms a redirection point after approximately one loop at which it traverses under itself and then crosses over the neighboring wire windings along the axis of the coil until it is redirected to run parallel to the other wire layers around the coil body. Thus, the windings of different wires alternate in a predetermined manner along the coil axis.

Abstract: The invention provides a switching power circuit and an insulating converter transformer. A tertiary winding to be formed on the secondary side of an insulating converter transformer is coiled in such a manner as to achieve a state of tight coupling with respect to a primary winding on the primary side of the insulating converter transformer and also to a secondary winding on the secondary side thereof, so that the peak value of a secondary current outputted from a second half-wave rectifying circuit can be reduced by the tertiary winding of the insulating converter transformer.

Abstract: The present invention relates to the methods of construction for inductive components of, preferably, ferromagnetic materials such as inductors, chokes, and transformers when used as an integral part of the fabrication of PCB's or FLEX's. In one preferred embodiment, holes are formed through a ferromagnetic substrate and plated with conductive material. The arrangement of these holes, and the subsequent design that ensues, will form the inductive components within the plane of the media in which the device is formed; using the substrate for a magnetic core. By using this approach, the inductive components can be miniaturized to physical sizes compatible with the requirements of modem surface mount technology (SMT) for integrated circuitry (IC). This process also allows these components to be fabricated using mass production techniques, thereby avoiding the need to handle discrete devices during the manufacturing process.

Abstract: The invention relates to a mid-frequency high power transformer which is specially used as a welding transformer in resistance welding, comprising a primary winding penetrated by the limb of a transformer core and a secondary winding which are configured as concentrically overlapping cylindrical windings. The windings of the primary windings are formed by a plurality of spirally wound layers of a relatively thin electrically conductive metal strip material, and the windings of the secondary winding are formed by an appropriate number of spirally wound layers of a thicker electrically conductive metal strip material chosen according to the desired reduction ratio between the primary and the secondary windings.

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 radio frequency (RF) choke having improved insertion loss and reduced modulation hum. The choke includes a core having first and second end portions which have similar magnetization and saturation characteristics, and which may be of equal or unequal diameters. A plurality of turns of a first conductor encircle the first end portion of the core in a first direction to define a first winding. Pluralities of turns of a second conductor encircle the second end portion of the core in the opposite direction to define second and third windings. The numbers and spacings of the turns of the first winding are so related to the numbers and spacings of the turns of the second and third windings that relatively low frequency currents flowing through said windings generate substantially canceling fluxes in the first and second end portions of the core, while relatively high frequency currents flowing through said windings do not generate substantially canceling fluxes in the first and second end portions of the core.

Abstract: An integrated transformer and inductor assembly for use in soft switching or resonant power converters, and the like. The assembly has a planar structure and includes a planar transformer and a parallel inductor. The assembly has a transformer core with a central gap. Planar interleaved primary and secondary winding are separated by insulating layers and are disposed within the transformer core. The parallel inductor is provided by a concentric inductor (reactive) winding disposed adjacent the center of the transformer core, which may be wound around a bobbin. The concentric inductor (reactive) winding carries inductor current, while load current flows mostly in the planar windings. Loss due to magnetizing current is substantially reduced in the present invention.

Abstract: Embodiments include a method for depositing material onto a workpiece in a sputtering chamber. The method includes sputtering a target and a coil in said sputtering chamber. The coil may have a preformed multilayer structure formed outside of the sputtering chamber. The outer layer of the coil may act as a secondary source of deposition material. The multilayer structure may be formed with an inner region or a base metal and an outer layer of a sputtering metal. The outer layer may be formed using a process such as plasma spraying, arc spraying, flame spraying, ion plating, chemical vapor deposition and electroplating.

Abstract: A method of winding a step-up transformer substantially minimizes the parasitic capacitance effects between the primary coil of the transformer and the secondary coil of the transformer. The primary coil is wound around a sectional bobbin and laid upon the bobbin in a winding direction that is opposite to the winding direction of the secondary coil. The opposite winding directions allow the high-voltage terminal ends of the primary and secondary coils to be maximally separated. The maximal separation of high-voltage signals within each coil reduces the effects of the capacitive coupling between the coils, and also maximizes the breakdown voltage between the coils. In a preferred embodiment, the auxiliary coil of the step-up transformer is also configured to minimize the effects of capacitive coupling and to maximize the breakdown voltage among the coils.

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 combined-type coil device provided with a core, a first coil and a second coil, where the core is provided with at least four through holes and the through holes are roughly parallel to one another. When a combination of two through holes constitutes a first through holes pair and the combination of the remaining two through holes constitutes a second through holes pair, a center line passing through the centers of the holes in the first through hole pair and a center line passing through the centers of the holes in the second through hole pair extend almost perpendicular to each other. The first coil passes through the first through hole pair, whereas the second coil passes through the second through hole pair.

Abstract: A novel inductor termed a suspended printed inductor (SPI) and an LC-type printed filter constructed using the suspended printed inductor is disclosed. The LC-type suspended printed filter is formed over any suitable substrate material, such as a dielectric substrate, with greatly reduced effects on filter performance due to the characteristics of the material. SPIs are characterized by the absence of a ground plane. A ground plane may physically still exist but it is located at a sufficient distance form the printed circuit board such that the distance can be considered virtual infinity from an RF circuit perspective. A number of different types of inductors can be fashioned as a suspended printed type inductor, including serpentine line inductors or transmission line inductors. The suspended printed inductor can be utilized to construct numerous types of filters such as low pass, high pass, band pass, band stop or any combination thereof.

Abstract: An RF induction coil for inductively coupled ionized sputtering applications having at least one extremely smooth surface, on the order of about 30 &mgr;m or less, which faces, substantially resides within, or is immediately proximate a plasma field in a sputtering chamber. The smooth induction coil requires only an extremely short burn-in time to remove surface damage and contaminants until a steady-state sputtering rate is achieved. The smooth induction coil may be constructed of target material, or a material distinct from the target material, and can be of any suitable geometry or configuration.

Abstract: A changeable display element is edgewise mounted on an insulating board and carries to rotate through about 180.degree. to show one color face or the other to a viewer. The board provides a similarly colored face for each face to form a pixel. The element carries a permanent magnet and is driven by a switchable magnetic field provided from the board. Soft iron pads on the board cooperate with the magnet on each position to retain the element against incidental displacement between application of the field. The board may support arrays of such elements.

Abstract: In one embodiment of the present invention, a transformer includes a first secondary winding made of stamped and bent metal. This first secondary winding has a coil portion with substantially closed cross section. The transformer also includes a primary winding made of wire and having a coil portion wound around the coil portion of the first secondary winding. A second secondary winding made of stamped and bent metal and having a coil portion with substantially closed cross section has its coil portion disposed about the coil portion of the primary winding. The primary winding further includes a second coil portion wound around the coil portion of the second secondary winding. The transformer thus provided is easier to build and less apt to internal short-circuiting than alternative designs.

Abstract: A transformer includes a divided primary winding in an isolating transformer power supply circuit and a secondary winding between the parts of the primary winding, a magnetic core having an air gap, and a bobbin surrounding the core with the individual windings applied to it, the transformer has a row of terminal posts to which the windings are connected is designed so that the primary winding is divided into at least three partial windings. The, the secondary winding that is under the highest load for the longest period of time is divided into at least two partial windings, the partial windings of this load secondary winding are enclosed by two partial windings of the minimum of three partial windings of the primary winding on the bobbin, and optionally one or more additional secondary windings are arranged outside the winding structure of the partial windings of the primary winding and load secondary winding.

Abstract: This element comprises a winding (4, 5) wound on a rectilinear magnetic core formed by various ferrite rods (1, 2, 3) placed side by side as in a bundle, and the winding is wound partly in one direction (9) and partly in the other (10). Application: Cable television distribution.

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: A transformer has a bobbin made of a resin material having flanges (2a to 2f) formed thereon, at least three chambers defined between the adjacent flanges. A primary auxiliary winding (P2), which supplies an electric power to an drive-control and overvoltage protection circuit and a primary excitation winding (P1-1) are wound on the chambers (3a and 3c) with at least one chamber (3b) disposed therebetween. A secondary winding (S2) which consumes the electric power always is wound on the chamber (3b) between the chambers (3c and 3a) on which the primary excitation winding (P1-1) and the primary auxiliary winding (P2) are wound.

Abstract: The present invention provides a small, light-weight converter transformer of high efficiency which has an excellent noise characteristic, a high coupling and good output voltage characteristic, low temperature-rise and a high reliability, for use in a switching power supply to be built in an electronic appliance.

Abstract: A single-phase three-wire type transformer which forms secondary coils by duplex coils winding two conductors in parallel according to the division intersection connection and can reduce currents circulating inside of a circuit of the transformer, thereby reducing the loss in the transformer. Coils A and B are formed in two opposing locations of a core (1). The coils A and B are configured so that two secondary coils and a primary coil are overlapped and wound in sequence from the inside of the core (1) in three layers, respectively. Each of the secondary coils provided by winding two conductors of small diameter in parallel condition on the core (1). One duplex coil connects the two parallel winding conductors in series with the other duplex coil, i.e.

Abstract: A changeable display element is edgewise mounted on an insulating board and carries to rotate through about 180.degree. to show one color face or the other to a viewer. The board provides a similarly colored face for each face to form a pixel. The element carries a permanent magnet and is driven by a switchable magnetic field provided from the board. Soft iron pads on the board cooperates with the magnet on each position to retain the element against incidental displacement between application of the field. The board may support arrays of such elements.

Abstract: Transformer (1) for switched-mode power supply, equipped with a former (6) having chambers (9), each chamber (9) containing windings (15, 16), each winding (15, 16) having an outer side surface (18) generated by a straight line moving parallel to an axis (AA') of the former, and characterized in that the generatrices of all the outermost surfaces (18) of the windings (15, 16) contained in each of the chambers (9) are identically the same for all the outermost surfaces (18) of the windings (15, 16) of each of the chambers, these generatrices thus forming a unique cylindrical surface parallel to the axis (AA') of the former (6).

Abstract: There is disclosed a high voltage transformer for a television receiver, comprising a coil former in which there are situated auxiliary windings, a primary winding over the auxiliary windings, and a high voltage winding over the primary winding. A first sleeve forms a flat base for the primary winding, and is arranged on the auxiliary windings. The primary winding is wound from a plurality of layers of solid wire, each layer disposed directly over the other, and a further sleeve made of a dielectric inserted between two of the plurality of layers.

Abstract: A board usually resembling a PCB or a PWB mounts a display element, whose appearance in a viewing direction is controlled by the sense of magnetization of a core which extends through a bore in the board. A conducting coil formed on the surface of said board is located so that current in said coil will magnetize the core.

Abstract: A triple core transformer including a coupler connected to a third core between two primary windings. Two sets of twisted pairs are wound around each primary core such that a strand of each pair communicates with primary each core. One strand of each pair is wound denser than the complementary strand of that pair. The denser strands are connected to a third winding around the third core. The third winding is wound in a series of segments. Each of the segments is connected to the preceding segment in a wire twist.

Abstract: A wideband audio output transformer for use with a push-pull vacuum tube amplifier using a multifilar ribbon in which primary windings and secondary windings coexist. The multifilar ribbon is wound continuously around a common core side by side to form successive layers. The primary windings are connected in series by turning the multifilar ribbon after the layers of multifilar ribbon have been wound and connecting the trailing end of the multifilar ribbon to the beginning end of the multifilar ribbon. Two additional wires are added in parallel with wires of the primary windings in the multifilar ribbon to redistribute the effective capacitance throughout the windings. The winding scheme eliminates the signal imbalance of an output transformer with a balanced push-pull primary winding and an unbalanced secondary winding at high frequencies.

Abstract: An inductor (100) optimized for surface-mount vacuum-pickup automated circuit assembly eliminates the expense of an inductor housing. The inductor has a hollow rectangular ferrite core (101) and a winding defined by a stripline (102) deposited on the core surface. Winding ends are formed by conductive vias (103) in the core that open onto the core surface, where they connect and mount the inductor to a circuit board (150). A flat sheet (104) adhered to one face of the core provides a surface for vacuum pickup and for labeling of the inductor. The core of a passively tuneable inductor (200) defines multiple unconnected winding segments (102-103). Segment ends mount the inductor to the circuit board and connect the segments to circuit board striplines (254) that are laid out in a pattern to interconnect a number of the segments into a winding. The inductor is tuned by changing the stripline layout and thereby varying the number of interconnected segments.

Abstract: A board usually resembling a PCB or a PWB mounts a display element, whose appearance in a viewing direction is controlled by the sense of magnetization of a core which extends through a bore in the board. A conducting coil formed on the surface of said board is located so that current in said coil will magnetize the core.

Abstract: A radio frequency choke for use in a cable television transmission and distribution circuit is disclosed. The radio frequency choke comprises a core of zinc-ferrite material as provided by MMG/NEOSID, Ltd., part number 31P0250012, and a wire coil wound around the core. The coil includes a first lead, a first clockwise winding of N1 turns around the core, the first lead being connected to an input of the first winding, a second counterclockwise winding of N2 turns around the core, a third counterclockwise winding of N3 turns around the core, and a second lead connected to an output of the fourth winding. In a preferred embodiment, there are six turns in the first clockwise winding, five turns in the second clockwise winding, and five turns in the third counterclockwise winding. Moreover, in the preferred embodiment, resonance damping resistors of approximately 2 K.OMEGA. are connected between the windings of the radio frequency choke.

Abstract: A balanced to unbalanced transmission line transformer is disclosed performing impedance transformation with improved frequency response across a wide operational bandwidth. The transmission line transformer significantly improves low frequency output balance by adding an additional transformer winding. The additional winding improves the low frequency response to less than 0.2dB across a given design bandwidth.

Abstract: In an amplifier module circuit, an input transformer (TI) transforms an input signal (ISU) into a transformed input signal (ISB), which is supplied to a pair of amplifiers (AMPA, AMPB). In addition to windings (W1, W2) for input signal transformation, the core (CO) of the transformer (TI) is provided with an auxiliary winding (W3) for biasing the pair of amplifiers (AMPA, AMPB). A DC bias voltage (VB) is supplied to a tap (XT) on the auxiliary winding (W3) whose ends are DC coupled to the input transistors (QA, QB) of the pair of amplifiers (AMPA, AMPB).

Abstract: An inductive coupler forming a closed magnetic circuit by mating a primary core assembly having a primary winding and a secondary core assembly having a secondary winding for transferring electrical power from the primary winding to the secondary winding by electromagnetic induction. A thin magnetic protective sheet having high permeability is attached to the mating surfaces of at least one of the primary and secondary core assemblies or placed to be held by the core assemblies. The magnetic sheet can protect the mating surfaces of ferrite cores, if such cores are used, from breakage by absorbing and dispersing the shock of impact caused when the mating surfaces are abutted against each other to close the cores. Provision of a slit or slits in the magnetic protective sheet can reduce eddy currents flowing in the magnetic sheet.

Abstract: A superconducting transformer comprises a superconducting primary layer arranged to conduct an externally supplied primary electric current around a primary core to establish a magnetic flux through the primary core. The superconducting primary layer is formed on a primary substrate of electrically insulating, non-magnetic material. A superconducting secondary layer is arranged to conduct a secondary electric current around a secondary core. The superconducting secondary layer is formed on a secondary substrate of electrically insulating, non-magnetic material. The primary and secondary cores are made of a non-saturating material. The secondary electric current is generated by stacking the layers to couple the magnetic flux from the primary core to the secondary core. Superconducting vias are formed through the primary, isolation, and secondary layers for making external connections to the transformer.

Abstract: A transformer which has a core, a wire for a primary coil and two wires for a secondary coil. The wire for a primary coil and one of the wires for a secondary coil are wound around a body of the core together, that is, are bifilar-wound. The other wire for a secondary coil is single-wound around the bifilar-wound wires. The two wires for a secondary coil are connected in series to form a secondary coil, and the wire for a primary coil forms a primary coil by itself.

Abstract: An electrical component includes a plurality of laminated layers 34, 44, 53, 64, of ferrite material, each layer having a conductive coil 40, 50, 58, 70 printed thereon. The conductive coil is formed by first printing a conductive sheet material 36, 48, 56, 68 on top of the ferrite layer, and then by exposing the conductive sheet material to a burst of laser energy focused in a predetermined pattern which cuts the coil out of the conductive sheet member.

Abstract: A composite winding type inductor having a stacked-layer structure formed by stacking a plurality of sets of electrically conductive strips for forming plural sets of coils alternately with a plurality of electrically insulting members. The electrically conductive strips in each of the sets are connected to the adjacent ones by way of edges of the electrically insulating members to thereby form a coil. A plurality of the coils thus formed turn around substantially a generally common axis. At least two of the plural sets of the electrically conducting strips are stacked in layers in such a manner as to follow spiral paths in the directions apposite to each other. The coils formed by at least two sets of the electrically conductive strips are connected to each other at least at one of a start end portion, an intermediate portion and a terminal end portion of the coil.

Abstract: A printed coil, having good magnetic coupling, low loss, and good high frequency characteristics, comprises a plurality of conductor forming planes on which a conductor pattern having one or more turns are formed centered about a core inserting hole and which are laminated together with an insulating layer, each of the conductor forming planes being provided with outer peripheral connecting holes provided on an outer periphery of the conductor pattern, and a plurality of inner peripheral connecting holes provided on an inner periphery thereof, with the outer and inner peripheral connecting holes being connected to the conductor pattern; a connecting coil which is laminated together with the conductor forming planes and having a connection pattern thereon for connecting the outer and inner peripheral connecting holes, and circuitry for electrically connecting the outer and inner peripheral connecting holes and the connecting coil.

Abstract: An output transformer for use with a push-pull vacuum tube amplifier using a multifilar ribbon in which primary windings and secondary windings co-exist. The multifilar ribbon is wound continuously around a common core side-by-side to form successive layers. The primary windings are connected in series by turning the multifilar ribbon after the layers of multifilar ribbon have been wound and connecting the turned end of the multifilar ribbon to the beginning end of the multifilar ribbon. The winding scheme increases the coupling between the first half primary, the second half primary and the secondary without reducing performance at high frequencies. The secondary windings are connected in series or in parallel to obtain the proper turns ratio for the transformer. A method of interconnecting the secondary windings for different turns ratios is also provided.

Abstract: Plane sheets which have the same shape as the magnetic circuit and are relatively movable along their contact surface are arranged in a stack. The stack is grasped and part of the circuit is bent out of alignment with the plane of the sheets to enable a coil to be placed on a portion of the circuit which is next to the air gap, whereafter said part is bent back into alignment with said sheets.

Abstract: An improved phase angle regulator with about 70% of the total impedance in the series unit and 30% in the excitor unit. In order to balance the physical size of both units, the excitor unit includes an interleaved winding arrangement. On large phase angle regulators, the higher impedance in the series unit allows for the use of a three-leg core design, and the low impedance interleaved excitor unit can also be designed on a three-leg core. The higher impedance series unit reduces the zero sequence current in the unit by about 40% during a single line to ground fault. Also the interleaved winding arrangement in the excitor unit improves its short circuit withstand capability.

Abstract: Transformer coil consisting of an insulating ribbon comprising electrically conducting patterns making it possible to produce paralleling of the patterns when this ribbon is accordion folded.According to the invention, one side of the insulating ribbon (25) alternately comprises one face (34; 36) with pattern (26; 27) and one face (35; 37) without pattern, each pattern (26, 27) comprising two paralleling pads (28, 29; 30, 31) prolonging each of its extremities beyond a separation line (P1, P3) in order to overlap onto the face (35; 37) without pattern in such a way that the paralleling pads (28, 29; 30, 31) of each pattern (26, 27) come into electrical contact with the extremities of the neighbouring pattern (26, 27) when the ribbon (25) is accordion folded, in such a way as to produce paralleling of the patterns (26, 27).The invention applies especially to the production of high-frequency transformers used in switched-mode power supplies.