This circuit, found in a publication from the 1970s, uses two PNP power transistors that can be replaced by 2N2955, PNP version of 2N30545 or even 2N3055 with the inversion of the battery polarity. The output is 450 V x 250 mA and the input 28 V. The transformer is made with 200 turns of wire 18 for the primary and the secondary with 1,550 turns of wire 28 in an appropriate form. Transistors must be equipped with excellent heat sinks.
