Abstract: An inductive device comprises an electric winding component having a generally toroidal shape, and a plurality of discrete magnetic components at least partially embracing the electric winding component so as to complete a magnetic flux path and to form at least one gap between end portions of the plurality of discrete magnetic components.

Abstract: A transformer for switched mode power supplies and the like comprises an input stage transformer section which is designed for very good coupling and very low primary leakage inductance, without regard for insulation above "working insulation" or for interwinding capacitance. One or more additional stage transformer sections are optimized for very low interwinding capacitance and very high dielectric isolation. The secondary of the input stage drives the primary of the next stage, so that the transformer stages are in series. Accordingly, the total interwinding capacitance from end to end is very low and the total dielectric isolation from end to end is very high. The secondary of the input stage transformer is isolated from both the input and the output, so it can be grounded as a safety ground.

Abstract: An operator controllable transformer having a variable inductor with a control coil is provided. The transformer includes phase control circuitry to control the output of the transformer by phase controlling current flow in the control coil, thereby controlling the current provided to the load.

Abstract: A soft-switching circuit for achieving zero-voltage-transition (ZVT) type commutation in switching power converters includes a magnetic feedback circuit for achieving substantially zero voltage turn on of the active power switches and for achieving zero voltage turn off of the passive power switches of the switching power converter.

Abstract: An operator controllable transformer having a shunt magnetic path with a control coil is provided. The transformer includes phase control circuitry to control the output of the transformer by phase controlling current flow in the shunt coil, thereby controlling the flux through the shunt magnetic path and the flux coupling with the secondary coil. Power for the control circuitry is derived from the current induced in the shunt coil.

Abstract: A high frequency matrix transformer comprises a plurality of interdependent magnetic elements interwired as a transformer. The various component parts of the high frequency transformer are arranged and interwired to provide a transformer having very low leakage inductance and very good coupling from the primary to the secondary. The high frequency matrix transformer is particularly well adapted for transformers requiring high equivalent turns ratios, high frequency, high power, and high dielectric isolation. It can have a plurality of parallel secondaries, which can source current to parallel rectifier circuits with current sharing. It can also have a plurality of parallel primary circuits, which also will current share, to balance the load between source switching circuits, or to provide dual input voltage capability (i.e., 120/240 volts). The high frequency matrix transformer tends to be spread out, and can be very flat, making it eaasy to ventilate or heat sink.

Abstract: A variable-ratio transformer for arc and plasma setups, comprising a magnetic core made up of a main part composed of two yokes and legs in accordance with the number of phases and an additional part disposed on the side of the yoke of the main part of the magnetic core. The additional part of the magnetic core is made up of a yoke and legs whose number is equal to the number of the legs of the main part, at least one leg being placed with a gap in relation to the first yoke of the main part. The primary winding of each phase comprises two series-connected parts, the first part being located on the main part of the magnetic core, while the second part is located on the additional part thereof. A controlled electronic switch which regulates the load current flowing through the secondary winding of each phase, disposed on the main part of the magnetic core, is connected in parallel to one of the parts of the primary winding of each phase.