HOW DOES A TESLA COIL MAKES MUSIC?

How It Works

The Tesla coil is a form of resonant transformer invented by Nikola Tesla and used for experiments with artificial illumination, for example, the transfer of power to the light source without cables.

The Tesla coil has two resonant circuits (primary and secondary circuits) inductively coupled and tuned to the same resonant frequency. The modern version, frequently called DRSSTC which stands for Dual-Resonant Solid State Tesla Coil, drives these resonant circuits actively with transistors to make it capable to play music through electrical discharges.

Getting into technical details
Three-phase full-bridge inverter supplies the energy demand of the primary circuit with buffet capacitors. The primary circuit, consisting of the primary coil and tank capacitor, is a resonant circuit. The adequately modulated inverter changes the direction of current flow in the same period as the resonant frequency of the primary circuit. At that moment, the resonant current of 2kA is flowing in the primary coil and primary circuit is building up energy in the form of the magnetic field which generates one million volts as results of geometrical arrangements and inductive coupling.

The secondary circuit, consisting of the secondary coil and top load, is a resonant circuit. The secondary circuit needs to be tuned the same resonant frequency as the primary circuit in order to the stored energy in top load achieve the highest amplitude, i.e. the longest arches. With the switching frequency of the inverter, electrical discharges create such pressure waves, which make them possible to play melodies.

How It Makes Music

Start with understanding what sound is
The sound is a pressure wave. Every sound produced by vibration. Vibration is the quick, back-and-forth movement of an object. When any object vibrates causing the air around it to move and forming sound waves. Frequency is the number of complete back-and-forth vibrations of a particle of the medium in a second. Sound’s pitch is determined by the frequency of the wave.

The science behind musical Tesla coil
A Tesla coil, best described as a form of plasma speaker, uses the expansion and contraction of air due to heating from plasma. Pressure waves at the audio frequency have been created through the bursts of sparks. A burst of sparks fires at every peak of the audio signal. The rapid firing of the sparks is faster than your eye can resolve, so it looks continuous, but in reality, the spark is forming and extinguishing at intervals of the audio frequency. By modulating the sparks’ output, musical tones are produced.