60KVolt Pulse Generator
Introduction
Here is a different kind of HV source producing single pulses at a considerably high voltage and high current (see also Jochen's High Voltage Page). This device is simple to build, but it is made up by special components like High Power SCR, Power Diodes and a big electrolytic capacitor (note: if you can't find the right type of diode, you can use any fast-switching diode capable of 1000V at 8A ). You need also two car ignition coils preferably "high power" ones that can be bought from a Car-Demolitor for few money. Pay attention to connect the primaries of the two coils anti-parallel so the secoundaries give voltage of different sign. The trigger-circuitry and the SCR can be substituted by a relay switch or just two blank cable ends: they work as nice as the SCR, but the contacts will burn soon.
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Theory
The capacitor C1 is charged with rectified mains voltage (about 310V) and is discharged in a moment trought the SCR on the primaries of the two coils. If you use a single-diode instead of a rectifier bridge, you don't have to disconnect the mains because the SCR can open the circuit during the negative half-wave. Close the SCR by hand or with the pulse generator at about one pulse per second max.
Safety Hints

  • - Don't touch the fotoflash transformer primary because the secondary is crossed by rectified mains voltage.

  • - Mount any power component ( like R1, SCR, D1 and D2 ) on a heatsink cooled by a 220V fan.

  • - Pay attention to the capacitor C1: it may not be able to discharge high-current pulses and it may get hot quickly or even explode.

  • - Don't touch the heatsink because the SCR's tongue may not be insulated from mains.

  • - It's better if you always use the SCR instead of the two blank cable ends: because the last solution doesn't grant a safe insulation.

  • - Last obvious suggestion: don't touch the high-voltage terminals.