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 If you follow the instructions on this site you will end up with a Stun Baton which takes a 4 volt battery and converts it to 10,000 volts of sparking fun. Of course be very careful if you decide to take on this project since the voltages created can do some serious harm.
Thanks for the tip Isaac R.
“The Royer Oscillator magically turns the ~13 volts at 700mA applied to its input, into just under 900 Volts AC at a couple of milliamps at its output – They’re usually made for 12volts, but we’re being naughty here. Finally, we feed the ~900 Volts AC into a twelve stage Villard Cascade (a type of Voltage Multiplier). The gives us ~10 kilovolts across our output sparkgap, with a fire rate of 5 ~ 10Hz.”