Here is the schematic diagram of 120 V to 12KV power supply, or you may call it high voltage generator or 120V to 12KV converter. This circuit produce very high output voltage that is about 12K volt with very small current of about 5 microAmpere.
Two SCRs form two pulse generator circuits. The two SCRs discharge a 0.047uF a 400v capacitor through a xenon lamp trigger coil at 120 times a second.
The high voltage pulses generated at the secondary of the trigger coil are rectified using two 6KV damper diodes. The voltage doubler circuit at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV.
Warning: Although this circuit can’t produce a lot of electric current, please be very careful with this circuit. A 12KV spark can jump about 0.75 of an inch so the electronic circuit needs to be carefully wired with lots of space between the components.