A Tesla coil, a resonant transformer circuit invented by Nikola Tesla that generates very high voltage, radio frequency alternating current electricity at low current levels. This example is an educational kit for use in classroom demonstrations. It probably produces on the order of 100 kV at frequency of around several hundred kilohertz. It consists of a step-up transformer "(right)" which produces several thousand volts, a pair of Leyden jar capacitors "(center)" a spark gap "(not visible)" and the resonant "oscillation transformer", "(left)". The high voltage is produced between the ends of the coil and jumps across the gap between the wires above the coil.