This project started in 2018 after stumbling upon some YouTube videos of musical tesla coils. A tesla coil is, basically, an air-core transformer that is excited at its resonance frequency. The capacitive element of the circuit required for resonance is the stray capacitance of the coil. For this particular implementation there is no resonant tank on the primary side (this is not a dual resonant coil ). The resonance frequency is around 400 kHz depending on the surroundings. The 3-turn primary is driven directly by a MOSFET-based half-bridge, that generates a square pulse at the resonance frequency. The feedback mechanism that regulates the switching frequency relies on a piece of enameled wire that acts as an antenna and it is based on Steve Ward's design.

Switching ON and OFF the excitation circuit at an audible frequency can produce sound as shown in the video.