Home Projection Television: Part II. Pulse-Type High-Voltage Supply

The performance of rectifier circuits of the voltage-multiplier type, energized by voltage pulses occurring in an inductive load in the plate circuit of a sawtooth-driven, biased beam-power tube, is briefly analyzed, and formulas are given for the internal resistance of circuits of this type comprising any number of stages. A method for substantially reducing the internal resistance by means of automatic bias control of the driver tube is described. Various factors determining the optimum number of rectifier stages for a given output voltage are discussed. An exceedingly compact high-voltage supply having automatic voltage control and furnishing 25 kilovolts for projection-type television tubes is described. This unit employs a voltage-tripling circuit with miniature rectifier tubes, the cathodes of which are indirectly heated by pulsed energy. A newly developed low-loss magnetic ferrite material has been successfully applied in the high-voltage supply.