It is a well known fact that every mad scientist needs lightning – it is a prerequisite to any evil lair. I chose the Marx Generator and Cockcroft-Walton generator because of their historical significance and impact on physics (used in the first particle accelerators, triggers for the first nuclear bombs, radar pulses, x-rays and TEA lasers). An ideal generator should produce 50 000V, in reality the final build produced somewhere between 30 000V and 40 000V (calculated based on length of spark gaps).
The system consists of two separate circuits. The first is a Cockroft-Walton voltage multiplier. It takes 120V AC off main and converts it to about 5770V DC. This DC current then slowly charges up the actual Marx Generator.
Cockroft-Walton Voltage Multiplier
The Marx generator functions by using a clever arrangement of capacitors. It charges each capacitor to 5770V in parallel using the CW multiplier. Once one the capacitors are charged enough the voltage becomes so great that it is able to jump over a spark gap to the next capacitor. This starts an avalanche that causes all the capacitors to discharge in series. As a rule of thumb a 1mm gap can be jumped by 1.1kV (assuming perfect spherical electrodes in dry air).
Fused Cockroft-Walton Voltage Multiplier
Building the Marx Generator
Here you can see the Full Discharge on the Right and the Small Series Capacitor Discharges on the Left
A Closeup of the Output