It is easy to see that building a simple
high voltage power supply with parts just laying around is not
that difficult. The goal was to accomplish the task of producing
a medium current
high voltage spark gap power supply. The simplicity comes with a price. This kind of circuit has no control over oscillating frequency or pulse width. The oscillator is free running.
The flyback joule thief circuit. The high
voltage feedback is what keeps an LED blinking when a battery
appears "dead" I reasoned that it should be easy to build a much
powerful version by just up sizing the components. So lets take a look at the basic circuit diagram of a "joule thief".
So all I needed was a much bigger coil. I pulled out of an old UPS Backup. I also
needed a 1K ohm resistor that could handle at lease 25 watts. Instead of a battery. I used an old 24 volts DC dell laptop power supply for input power. For my NPN transistor.
I just used any generic low frequency general switching NPN power transistor I had laying around. You simply need to look up the transistor and make sure what ever your
DC power supply is. That the NPN transistor you choose can handle what ever voltage your salvaged DC power supply is rated for. The feedback is connected in parallel with
the primary winding of an old CRT high voltage flyback transformer I was able to use. The high voltage side of the flyback is what feeds this big noisy spark gap.
alert! If you are going to try anything like this. Please be safe
and follow all common sense safety precautions. If you don't know