Abstract: This invention relates to the resin encapsulation of solenoids to achieve water resistance at pressure depth. When a compatible and bondable resin is used to form a solenoid bobbin, to insulate the lead-in wires and to encapsulate the solenoid, the resulting encapsulation is effective in resisting water penetration. The formation of bonds between the encapsulation and the solenoid bobbin flanges and insulated lead-in wires allows the encapsulated solenoid to resist water penetration and to operate efficiently in underwater environments.

Abstract: An improved transformer coil of the type characterized as a shell-form or pancake coil used in large scale power transmission transformers. The improvement adds strength to resist lateral edge coil deformation as a result of handling the coil during transformer assembly and as a result of fault current surges. The improvement is directed to tightly spread tapeing some of the inner and outermost conductor turns together with preferably a heat shrinkable structural tape. This spread tapeing is periodic or spaced along the outer periphery of the coil for economy and may be staggered in terms of the number of conductor turns wrapped together. Preferably, the innermost conductor turns may also be spread taped in this same manner.

Abstract: A transformer and method of making a transformer is disclosed. The transformer has a magnetic core, a first winding and a second winding. The first and second windings are wound about the core, and an insulating jacket, which includes a plurality of protrusion, mounted about the core. One of the first and second windings is wound about the insulating jacket. The core is preferably a toroid core in one embodiment. Some of the anchors are on the inner diameter of the insulating jacket, and other on the outer diameter of the insulating jacket. The anchors are preferably spaced at equal circumferential positions. The windings are a progressive windings, with various sections, and each section has a number of layers. Each progressive section is anchored by at least two of the anchors. The first and second windings are wound directly on the core insulation, and the insulating jacket is mounted directly on the core.

Abstract: The apparatus for cooling a high power electrical transformer and electrical motors uses thermally conductive material interleaved between the turn layers of a high power transformer and iron core laminates to provide a low resistant thermal path to ambient. The strips direct excess heat from within the interior to protrusions outside of the windings (and core) where forced air or thermally conductive potting compound extracts the heat. This technique provides for a significant reduction of weight and volume along with a substantial increase in the power density while operating at a modest elevated temperature above ambient.

Abstract: An integrated circuit and method of manufacturing therefor. In one embodiment, the integrated circuit includes a substrate with an insulator and a capacitor formed over the substrate. The integrated circuit further includes an adhesive formed over the insulator. The integrated circuit still further includes a micromagnetic device. The micromagnetic device includes a ferromagnetic core formed over the adhesive. The adhesive forms a bond between the insulator and the ferromagnetic core to secure the ferromagnetic core to the substrate. The micromagnetic device also includes at least one winding, located proximate the ferromagnetic core, to impart a desired magnetic property to the ferromagnetic core. The micromagnetic device is electrically coupled to the capacitor.

Abstract: A surface-mount air-core coil has a coil body formed by winding a conductive wire spirally and mount legs formed by folding both ends of the conductive wire horizontally toward the inside. The lower surfaces of the mount legs are positioned below the lower surface of the coil body. The length of the mount legs is set longer than the width of the coil body.

Abstract: A transformer includes a core assembly having a coil, a core with at least a portion extending through the coil, and terminals for providing electrical connection with the transformer. The core assembly is impregnated with a thermally conductive material to form a unitary core mass. An outer coating which is also highly thermally conductive encapsulates the core mass. The outer coating includes a plurality of finned or ribbed surfaces that provide an increased heat transfer area to a surrounding cooling medium such as air.

Abstract: A data transmission micromagnetic integrated circuit having a ferromagnetic core, a method of manufacture therefor and a data transmission circuit employing the same. In one embodiment, the micromagnetic integrated circuit includes: (1) a substrate; (2) an insulator coupled to the substrate and (3) a metallic adhesive that forms a bond between the insulator and the ferromagnetic core to secure the ferromagnetic core to the substrate.

Abstract: A dry-type transformer having an iron core, with high voltage and low voltage coils encapsulated in casting resin. The high and low voltage windings may be cast separately, or together. Either or both of the coils may have integral axial cooling channels, as may the annular axial space between the inner and outer windings (usually low voltage and high voltage, respectively). Coil cross-section is a modified oval (Rectoval.TM.) shape, in that the sides of the coil are substantially linear and the ends of the coils are substantially semi-circular. The aspect ratio (L/W) of the coil, when viewed in radial cross-section, ranges from greater than 1.0 to about 2.5. The rectangular nature of the coil allows for the use of a core member having a rectangular cross-section, thereby reducing the manufacturing expense involved with shaping the core member. The circular nature of the ends of the coil provide improved strength similar to that of circular/cylindrical coils.

Abstract: An improved low voltage winding for dry insulated transformer has its windings resin encapsulated. The winding is constructed with flexible sheet conductors wound coincident with an insulating sheet material. Insulating spacers provide a means to form air channels in the windings during the coil forming process. A sealant is applied to openings at the lower ends and along vertical seams of the coil prior to the resin impregnation and encapsulation process. This will prevent drainage of the resin during a curing cycle. The result is a coil that exhibits high short circuit protection due to the tightly bond sheet conductors which will prevent movement of the conductors during short circuit conditions and also increases the radial compressive strength of the coil.

Abstract: A wire wound electronic component of the present invention includes a bobbin having a core 1a having a substantially circular cross-section and rectangular flanges 1b formed at both ends of the core. A groove 2 is formed in each side of each flange 1b. A conductive film or external electrode 3 is formed on each flange 1b. A coil or wire 4 is wound round the core 1a and has a conductor protruding from opposite stripped ends thereof. The opposite ends 5 of the conductor are respectively received in the grooves 2 of the flanges 1b and connected to the conductive films 3. A coating or armor 6 is formed on the coil 4 and has a flat surface 6a. The coating 6 has a rectangular figuration complementary to the configuration of the flanges 1b.

Abstract: A method and apparatus for manufacturing a variable insulated helically wound electrical coil is disclosed. Insulated rectangular wire is fed from a supply reel to a coating zone and within the coating zone liquid resin insulation is selectively applied to the wire so it has additional insulation only in those areas of the coil where the dielectric strength is needed. The insulated wire is fed through a curing station to allow curing of the additional insulation prior to winding the cured insulated wire into a coil. The cured insulated wire is wound into a coil of predetermined shape at a winding station whereby the portions of the wire having the additional insulatin are located in the areas of the coil where the greatest dielectric strength is needed. The timing of the resin application to the wire is coordinated with the winding of the coil so that the proper insulation thicknesses are achieved at the required locations in the coil.

Abstract: A surface-mount air-core coil has a coil body formed by winding a conductive wire spirally and mount legs formed by folding both ends of the conductive wire horizontally toward the inside. The lower surfaces of the mount legs are positioned below the lower surface of the coil body. The length of the mount legs is set longer than the width of the coil body.

Abstract: A package for an electronic device, the electronic device including a body having a cavity therein, the body subject to stress from imposition of forces. The package includes a conforming compressible material disposed within at least a portion of the cavity in the body and substantially conforming to an interior configuration of the cavity, reducing imposition of the forces within the cavity and thereby reducing the stress on the body.

Abstract: Epoxy resin casting compositions comprising(a) a liquid aromatic glycidyl or .beta.-methylglycidyl ether or a liquid mixture of several aromatic glycidyl or .beta.-methylglycidyl ethers containing on average more than one glycidyl ether group per molecule,(b) one or more than one acid hardener for the glycidyl ether,(c) a curing accelerator,(d) a filler mixture containing calcite and wollastonite in an amount from 40 to 60% by weight, based on components (a), (b) and (d), and as optional components,(e) customary additives for epoxy resin casting compositions are suitable in particular for coating or encapsulating electrical or electronic components and, more particularly, electrical ignition coils.

Abstract: A degaussing coil designed to be mounted on the glass panels of cathode-ray tubes used to display color images wherein, the link between the ends of the winding of the degaussing coil and the conductors provides connection to the electrical supply circuit is encased in an insulating thermoplastic material. The degaussing coils is utilized for color television receivers.

Abstract: An engine igniting coil device directly attachable to an igniting plug, wherein both primary and secondary coil bobbins have flangeless ends, the secondary coil bobbin has inwardly protruding ribs for coaxially supporting the flangeless end of the primary coil bobbin mounted therein and the secondary coil bobbin also has protrusions formed at its external wall apart from a high-voltage terminal of the secondary coil wound thereon and is coaxially mounted in a coil case by abutting its protrusions on an inner wall thereof, thus eliminating the possibility of damaging the bobbins by a large thermal stress produced in solidified insulating resin in a coil case by a differential thermal shrinkage in an axial direction and preventing a leakage current from a high-voltage side of the secondary coil bobbin to the coil case through a flange-like connection.

Abstract: A reed relay comprising a reed switch having a pair of leads and a magnetic coil assembly for driving the reed switch, the magnetic coil assembly being composed of a magnetic coil wound around a cylindrical bobbin having an insulating flange at each end of the cylindrical bobbin, a terminal insulator integrally continuous with each flange, and a plurality of terminal leads insulated from one another by each of the terminal insulators. One embodiment of the present invention is a cylindrical bobbin having an electric conductivity so as to act as an electrostatic shield for the reed switch inserted thereinto, and another embodiment of the present invention is a method for fabricating the magnetic coil assembly comprising a step of forming a cylindrical bobbin and the terminal leads in each side of the cylindrical bobbin by using a patterned sheet of metal, wherein the cylindrical bobbin is continuous with the ground terminal lead in each side.

Abstract: A molded transformer includes a transformer body including a coil bobbin having a spool having a central through-hole and a collar at each of two ends thereof, and a conductive wire, such as a copper wire, wound around the spool, and an EE type or EI type ferrite core which is inserted into the coil bobbin; and a thermoplastic resin for molding the transformer body in such a manner that only a terminal portion used for mounting is exposed through the resin. The resin has a low molecular weight, ensuring a low molding stress and a low melting viscosity.

Abstract: A bar coil for use as an ignition coil in internal combustion engines (of motor vehicles) is designed so that casting resin can be introduced into an interior space of the bar coil in a manner that is advantageous from a manufacturing standpoint. The bar coil has a centrally arranged channel that extends from a connecting segment, through a core of the bar coil, and to a pan-shaped bottom area of the interior space of the bar coil. Casting resin flowing through the channel enters the closed bottom area, from which it is diverted as a uniform front to flow through gaps in the bar coil to the connecting segment.

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: A semiconductor device is disclosed, comprising an integrated circuit formed on an upper surface of a semiconductor wafer chip and inductance formed on sides of the semiconductor wafer chip.

Abstract: A wire-wound inductor includes a dielectric core, terminals including wire staples that are crimped around the core, and a wire winding disposed about the perimeter of the core and connected to the terminals. A coating such as an adhesive coating is disposed over the wire winding and between the terminals. The process for manufacturing the inductors in a continuous process. Beginning with a spooled material, which may be extruded, inductors are formed on a core material sequentially. The inductors are not physically separated until the final stages of manufacturing, which is in contrast to the prior art method in which each inductor is individually constructed on an individual core that has been manufactured with tight tolerances and wound individually. By virtue of the characteristics of the inductor components, extremely tight tolerances (typically about 0.0005") can be obtained, resulting in highly controlled inductance values.

Abstract: "Molded products for high voltage apparatus comprising an" epoxy resin composition for molding comprising an epoxy resin (A), an acid anhydride (B), a curing accelerator (C), at least one coupling agent (D) and a filler (E). The epoxy resin (A) is a bifunctional brominated bisphenol A or a brominated bisphenol F, "epoxy resin and at least one bisphenol A, bisphenol F or bisphenol epoxy resin". The coupling agent (D) is selected from the group consisting of epoxysilane type coupling agents, phenylaminosilane type coupling agents, mercaptosilane type coupling agents and titanate type coupling agents, which has an average particle diameter of not more than 60 .mu.m and in which the content of particles having a diameter of not more than 5 .mu.m is not less than 5% by weight. The filler (E) comprises at least one of silica fillers or alumina fillers. The ratio of the number of acid anhydride groups of the acid anhydride (B) to the number of epoxy groups of the epoxy resin (A) is 0.5 to 1.

Abstract: An ignition coil for an internal combustion engine and a method of making the same in which layers of the secondary winding are separated by a non-filtering/non-segregating material embedded in an electrically insulated ignition coil housing. The preferred non-filtering secondary winding separator is a solid filament, non-absorbing/non-adsorbing mesh, such as a nylon mesh. Using the non-filtering/non-segregating secondary winding separator prevents filler damming when an ignition coil housing is manufactured using a vacuum encapsulation and curing process in which an encapsulation compound (e.g. a thermal setting epoxy) has solid additives (e.g. sand fillers). Non-absorbing/non-adsorbing separators are also advantageous because the separators do not alter the chemistry of the encapsulation compound.

Abstract: An isolation transformer comprises two core pieces mounted to cooperate to provide flux paths, one of the core pieces being shaped so that a central flux path is defined by a central leg of the core, at least two magnetically coupled windings surrounding the central flux path, and an isolation layer sandwiched between the windings.

Abstract: A non-metallic bobbin (22) has features on a radial flange (28) which allow magnet wire (MW) that forms an electromagnet coil (114) on the bobbin core (24) to be tensioned throughout. An end segment of magnet wire is wrapped around a post (56) on the bobbin flange, and the magnet wire runs in tension generally diametrically across the bobbin to pass through slots (66, 68) in opposite walls of an electric-terminal-receiving socket (60) also on the flange. The wire runs in grooved tracks (74, 70) proximate the socket to pass around the perimeter edge of the flange to the opposite flange face where it is wound in tensioned convolutions around the core to create the coil. It then runs in tension from the coil around the perimeter edge of the flange to pass through a second socket (62) having the same associated features as the first socket (60). From there the tensioned magnet wire extends back across the bobbin to be tied to the post.

Abstract: Prior to winding wire in a coil around a foil, the foil is coated on a least one surface side with a tacky silicone composition. A composition on the foil exerts a retaining force on the wires discouraging said wires from sliding away from an original or intended position.

Abstract: A degaussing coils designed to be mounted on the glass panels of cathode-ray tubes used to display color images wherein the link between the ends of the winding of the degaussing coil and the conductors provides connection to the electrical supply circuit is encased in an insulating thermoplastic material. The degaussing coils is utilized for color television receivers.

Abstract: A coil assembly for a solenoid valve includes a sealing member having a sealed cavity that generally encircles an opening containing an electrical lead extending from the windings of the coil. The sealing member is disposed within a encapsulating material that is pressure molded around the windings of the coil assembly. During the pressure molding process, the pressure from the molding process exerts a force on the outermost side of the sealing member and compresses the outer member. The force being exerted to the outermost diameter is transferred through the sealed cavity to the innermost portion of the sealing member forcing it into a forced intimate contact with the lead. The force on the lead is maintained after the pressure from the molding process is removed. This arrangement provides a seal between the lead and the sealing member that is effective to prohibit damaging elements reaching the windings contained in the coil assembly.

Abstract: A method of making an encapsulated transducer (10), which includes an injection molded encapsulation (20) having a front end (22) and a back end (24). The encapsulation (20) is a monolith of cured moldable material ensconcing a sensing element (90) proximate the front end (22) and a portion of an information transmitting medium (120) emanating from the back end (24). A component alignment preform (40) operatively couples the sensing element (90) with the information transmitting medium or cable (120). The component alignment preform (40) includes a front ferrule (70) and a rear ferrule (80) bonded thereto and linearly spaced apart along a long axis "A". The component alignment preform (40) further includes an annular recess (44) in which the sensing element or coil (90) is placed so that it is linearly spaced and aligned along the common long axis "A" in which the front and rear ferrules (70), (80) are aligned.

Abstract: A laminating type molded coil and a method of fabricating the same comprising at least one coil substrate structure in which coils are formed on both sides of an insulating substrate by use of a printed wire technique, resin sheets disposed on both side of the coil substrate structure, and insulating covering sheets disposed on the outermost surfaces of the resin sheets, wherein when heated and subjected to pressure the spaces between the layers and between the coils are filled with resin from the resin sheets, and then hardened to produce an integral structure. Advantageously, because the coil pattern has a predetermined shape and is formed by printed wire techniques, the thickness of the coils may be thin and the gaps between the coils may be narrow. By using the invention method, the fabrication does not require use of a molding box as does the conventional method and the fabrication is done with simple steps.

Abstract: A resin-rich electrically conductive felt material is described. The described conductive felt can be used to suppress corona discharge in high voltage generator coils. The conductive felt is prepared by treatment with electrically conducting polymers, such as polyaniline and polypyrrole, and resistivity values ranging from 4,000 to 100,000 ohms may be obtained. This treated felt can be readily impregnated with thermoset resins, such as epoxies, to provide flexible prepregs suitable for coil bonding applications in turbine generators.

Abstract: A single phase, dry type transformer has an iron core, high voltage windings embedded in cast resin, and low voltage windings resin encapsulated. The low voltage winding is constructed with flexible sheet conductors. Insulating material includes a means to secure the windings in place during a vacuum and pressure resin impregnation process. The result is a coil that exhibits high short circuit protection due to the tightly bond conductors comparable to completely resin encased molded transformers at a substantially reduced cost.

Abstract: In order to achieve improved mechanical properties for a coil (1), it is proposed to structure a first electroconductive winding (3) of the coil (1) as a coil former. This coil has a first connecting element (15), to which a second connecting element (17) is attached via an insulating part (25). The two connecting elements (15, 17) form the connections for the coil (1). In this way, a self-supporting coil structure is achieved. The coil (1) is particularly intended as an undervoltage winding with a low number of windings for cast resin transformers.

Abstract: A dry type transformer has an iron core, high voltage windings embedded in cast resin, and low voltage windings resin encapsulated. The low voltage winding is constructed with flexible sheet conductors coincident with layer insulation sheets that extend beyond the edge of the sheet conductor. Cooling air ducts are fabricated in the low voltage windings as it is wound. To prevent the extension of the layer insulation sheets from collapsing over the formed air ducts during a vacuum and pressure resin impregnation process, reinforcing means are added to the extensions to prevent them from collapsing.

Abstract: An encapsulated transformer includes a transformer coil assembly, a rigid core insert having an upstanding portion positioned within the hollow interior of the core and a base portion on which the core rests, and a thermoplastic rubber jacket that completely surrounds the transformer coil assembly and is bonded to the base portion of the core insert to provide a completely waterproof encapsulated transformer which is impervious to liquid and gasses that could be detrimental to the performance of the transformer. A method for producing such an encapsulated transformer includes placing a rigid core insert in a mold cavity of a mold, and positioning a transformer coil assembly in the mold cavity so that the transformer coil assembly rests on the core insert. Thermoplastic rubber is then injected into the mold cavity to completely encapsulate the transformer coil assembly in a jacket of thermoplastic rubber.

Abstract: A stator of a vehicular alternating current generator comprising: a stator core having slots; and a stator coil wound in the slots of the stator core; wherein a resin having a peak or peaks of a loss tangent which is a value of a loss elastic modulus divided by a storage elastic modulus in a temperature range of from 100.degree. C. to 250.degree. C. is provided among coil strands of the stator coil and/or between the stator core and the stator coil.

Abstract: A winding support body (6, 10) for transformers/reactors with a winding of a tape-formed superconductor (8), wherein the support body consists of a substantially straight, circular-cylindrical tubular body which, on the side where the winding is to be placed and out towards the two ends, is provided with a helical slot with a plane surface with a width equal to the width of the tape. In this way, each turn of the slot around the support body forms a surface which practically constitutes the envelope surface of a straight frustum of a cone. The angle (v) between a generatrix (9) of the envelope surface and the axial center line of the support body increases for each turn out towards the ends of the support body in such a way that the envelope surface at all points coincides with the direction of the magnetic field (FIG. 4 ).

Abstract: A conductive winding electrically isolated by reflowable material which is incorporated into a transformer further including individual layers of electrical insulation material. The transformer is formed in a layered configuration wherein isolation requirements set forth by safety certification agencies are met through the use of the reflowable material and insulation layers.

Abstract: An electronic component comprises an inductive element which includes a pair of zigzag parts, a pair of first terminals connected to one side of the zigzag parts, a connection part connected to the other side of the zigzag parts, an electrode disposed in the middle of the connection part, a second terminal provided on the extensional position of the electrode, and an exterior mold having a gap in the middle in order to expose the fronts of electrode and second terminal.

Abstract: An electronic component comprising an inductive element which includes a pair of coils, a pair of first terminals connected to one side of the coils, a connection part connected to the other side of the coils, an electrode disposed in the middle of the connection part, a second terminal provided adjacent the extended portion of the electrode, and an exterior mold having an opening in the middle in order to expose the front portions of the electrode and the second terminal.

Abstract: A stock material for winding into a magnet coil includes a running length of conductive aluminum metal having a cross section that has first and second long sides and two short sides. The long sides and short sides meet at corners which are substantially free of jagged edges and sharp corners. An insulating epoxy polymer coating uniformly about 0.001 inches (25 microns) thick covers the first long side and the short sides, with the second long side being substantially free of the insulating coating. A heat-activatable adhesive is arrayed non-continuously on one of the long sides.

Abstract: An improved core-form transformer is disclosed. The core-form transformer includes a c-wrapped ribbon conductor with opposing wide sides and opposing thin sides. The c-wrapped ribbon conductor is wound around a core to form a plurality of coil sections. Adhesive is applied directly to one of the wide sides of the ribbon conductor to form a strong mechanical coupling within the coil sections. A novel transposing fold of the ribbon conductor is employed to create coil transpositions. The core-form transformer of the invention reduces circulating current losses while utilizing only a small number of transposing folds, generally adjacent to a first coil section, a last coil section, and an intermediate coil section.

Abstract: Electrical isolation which is required between adjacent windings of a device such as a transformer is provided by wrapping a group of individually insulated conductive cores 62, 64, 66, 68 with multiple turns of a thin tape 32. Use of a thin tape rather than solid insulation provides a long creepage path from the cores 62, 64, 66, 68 to adjacent components. The invention can also be applied to components other than transformers.

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: A locating ring for positioning and supporting an electric coil within a mold for encapsulation of the coil. The locating ring comprises an annular body defining a central axis and a plurality of tabs extending generally axially from the annular body. The annular is adapted to insulate the coil from a steel shell. The tabs are adapted to position the coil within the mold. In a preferred embodiment, the tabs include a recess along a portion of the radially inner face thereof which receives the encapsulating material prevents the separation of the tabs therefrom. In an alternate embodiment, a portion of the sidewalls of each tab are tapered outwardly from the inner face to the outer face thereof. In another aspect of the invention, the body of the locating ring includes a plurality of circumferentially spaced openings extending axially therethrough which provide a number of routes by which air may be vented during the molding operation.

Abstract: A secondary ignition coil is wound around a bobbin having a plurality of slots therein. The slots are spaced around the cylindrical wall of the bobbin to provide for the rapid and uniform flow of resinous potting material through the slots in the cylindrical wall into the coil. Resin also flows from the outer portion of the coil winding into said coil winding.

Abstract: There are provided low profile inductor and transformer windings, and methods for fabricating the same. An elongate conductive ribbon is wound in one continuous direction on a generally hourglass shaped mandrel to form the ribbon into a double conical helix having a plurality of spaced apart coils. A sheet of dielectric material having an orifice therethrough is threaded to the midpoint of the double conical helix. The two sides of the helix are then compressed into planes such that the coils in each side lie flat and engage the adjacent side of the sheet of dielectric material. A compound inductor winding can be fabricated from a continuous conductive ribbon wound into a plurality of double conical helixes joined end-to-end. After compression, the compound winding consists of a low profile stack of spiraled windings connected in series, but constituting only one continuous ribbon having no internal connections.

Abstract: A mini-transformer features an iron or ferrite core (2) and primary and secondary windings (3, 4). Portions of the windings (3, 4) which extend beyond the iron or ferrite core (2) are covered on both sides with a thermoplastic material forming a lid (6, 7). The two lids or end bells (6, 7) are combined into one piece by means of first bars (12), which extend through the hollow spaces (9) between the windings (3, 4) and the iron or ferrite core (2) and fill them, and that the laminated iron or ferrite core (2) is fixed in itself by second bars (14) connecting the two lids (6, 7).