Circuit Project Electronic

The peak output voltage will be approximately 15,000 to 20,000 volts, but this will vary with the ignition coil type and the voltage at which the MOV starts conducting. Do not touch any part of the 555 circuit including any leads of the timing resistors or timing capacitor; doing so can inject interference into the [...]

Below is the schematic to a high voltage generator using one ignition coil. It runs fine on 6 volts, but you can change the 5 relay to a 9 or 12 volt relay, and run it on 12 volts. The average output (depends on the coil, the input voltage, etc…) is 40kV.
Related Links
More [...]

My EHT3 project uses a solid-state oscillator and ignition coil to generate a very high a.c. voltage (using a spark gap as a guide suggests ~40kV). The project uses two d.c. supplies: one for the oscillator part and one to supply the power to the coil. This makes the circuit a bit more complex than [...]