The tesla coil consists of a large capacitor bank that holds up to 200kv that is charged with a 6kv neon sign transformer. After the capacitor charges it jumps a spark gap and connects the primary tank circuit. 200,000 volts are pulsed through a primary coil made of copper tubing. this allows the energy to transfer to the secondary coil. the large red coil then amplifies the energy and the top load disperses it into an amazing display of lightning.