Marx generators are one of the simplest voltage boosters out there as they contain nothing but capacitors and resistors. Not only that, but they require no output resistor to limit the current. If you want to hear a crack, make a marx.

Below is a schematic of a marx generator and as you can see it contains only capacitors and resistors. The diode and transformer are the power supply. Notice the little ball shaped things with the sparks going through them; those are the spark gaps and they’re the heart of the marx generator. Also notice how the first gap is smaller than the rest.

At first all the capacitors are charged up through the resistors; something which takes a little while because the resistors are often of very high value [RC constants]. But then…

..when the capacitors reach a high enough charge, the voltage across the first spark gap becomes so great that the air breaks down and the charge jumps across. Since the spark gaps are arranged in a zigzag configuration, this puts the next capacitor in series with the last because of this the voltage has doubled. It then easily sparks over the next gap. All the gaps then fire in a cascade which creates a very high positive or negative voltage across the entire stack.

The spark gaps in a marx generator should be as round as possible, otherwise the electricity will leak away via corona discharge. The spark gaps in my marx generator were made by soldering little iron balls to the capacitors’ leads, then some heat shrink tubing was placed around the wire lead.

In order for the marx generator to work properly the first spark should occur at the first gap, so to encourage sparking the balls in the first 3 gaps were replaced with a piece of hair thin wire. Since pointy objects tend to have pointy electric fields, electricity prefers to leave them moreso than round ones. This made sure the initial sparks occured on the first few gaps.

Below we have the obligatory spark pictures and youtube video. Every pop is a spark, but the camera misses quite a few of them.