This is a circuit for the Nitrogen Laser power supply . It runs off standard household power of 120VAC 50/60Hz, and the output is adjustable up to 25kV or more. For use with 50Hz power, the variable autotransformer shown in the parts list below must be attached to the power line at the ends of the coil, and not the tap as shown in the schematic.source

This is the schematic use to generate high voltage using one ignition coil. It runs fine on 6 volts power supply. The average output (depends on the coil, the input voltage, etc…) is 40kV. source