to do this you need a suitable high current transformer 12-0-12 volts which i am attempting to make from a scrap microwave oven transformer by replacing the high voltage secondary (removed with a hacksaw and hammer) with a few turns of much thicker wire to use as a primary. each turn gives about 0.78 vac, so i put on two lots of 15 turns (16 might have been better). safety warning. the working insides of a microwave oven are most definitely absolutely lethal, the transfomer of which can supply something like 300ma at 2000+ dc volts, with the chassis acting as ground return plus a smoothing capacitor that can stay charged for a long time. under no circumstances mess under the cover of a microwave oven if you don"t know what you are doing. finally, if you rewind a transformer you cannot use it from the mains again as you cannot guarantee that the insulation is satisfactory.
