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This is my completed high voltage power supply, it is capable of generating up to 50kV at a relatively low current. It is mainly composed of savaged parts, the power input is composed by a 24 volt transformer salvaged from an old VHS, it is capable of delivering several amps without problems, the bridge rectifier was also salvaged, it is rated for 6 amps. The capacitors are rated 25 volts and 10000uF each (20000uF total).
The driver circuit revolves around a 555 timer with adjustable frequency and duty cycle (from 5-50kHz and 5-50% duty cycle), it has it's own 12v input independent from the transformer, which has an 8 volt output, but doesn't delivers enough current to charge the gates fast enough, leading to efficiency problems which translate into lower output voltage at the flyback.
The switching is performed by three IRF540N MOSFETs mounted on a huge heatsink, they barely get warm even under full load. The bridge rectifier though seems to get quite warm, but the heatsink takes care of it. The transformer also tends to get hot because it wasn't designed to deliver such amperages, but if the output of the flyback isn't short circuited or the arc is too short it can work without problems, and even if that's the case, it can still work for several seconds-minutes before getting too hot.
The flyback was recovered from a small and old TV. I tried with different flybacks and this one gave me the best results. When having a limited power input is preferable to pick the smallest flyback in order to keep the voltage high. If I was to use one of my bigger flybacks the voltage would be too low, although the current would be higher. The bigger the flyback is the more power it tends to draw, normally flyback transformers tend to "choke" themselves, specially when using more turns at the primary, a bigger flyback will be less reluctant to let the current pass if we compare to a smaller one even if the primaries have the same number of turns. This should be taken into account if you don't want to fry your power input circuit.
The total power consumption must be around 100W.
Other thoughts: The whiny high pitched noise comes from the frequency at which the flyback seems to operate best, and is set by the potentiometer connected to the 555 timer.
Thanks for watching, if you have any question please ask in the comment section.
