Abstract: The invention comprises a power transfer circuit for a plasma torch for smoothly and linearly transferring the plasma arc from the nozzle of the torch to a workpiece as cutting operation commences and vice versa as cutting operation is completed. The invention includes a switching transistor for alternately providing power to the nozzle or the workpiece and a freewheeling diode coupled between the workpiece and the power source. The transistor is responsive to the voltage differential between the workpiece and the nozzle for transferring the plasma arc therebetween. Below a specified voltage differential, the transistor is turned off such that all power is delivered to the workpiece. Above a specified upper voltage differential, the transistor is turned on and all power is delivered to the nozzle. Between the specified upper and lower voltage differentials, the transistor switches at a specified frequency, the duty cycle of the transistor (i.e.

Abstract: A pulse-width-modulated, switching power supply has a pulse width modulator, a full bridge network driving a pulse transformer, power switching section, a high frequency power transformer, an output rectifier and an output inductor. The power switching section includes two or more H-bridge networks each preferably having four FET's. The pulse transformer, controlled by the pulse width modulator, in turn controls the switching of the H-bridge networks. This switching is simultaneous in each H-bridge network, preferably to within 50 nanoseconds. The pulse transformer windings are coaxial and short. The outputs from the H-bridge networks are applied to in-phase windings of the power transformer. The power windings are segmented and wound on cores in side-by-side relationship to produce a "finite" mutual inductance among the primaries of the power transformer. This finite inductive coupling allows variations in the H-bridge power outputs of up to one dB.