What is a Tesla Coil?

It is a type of very high voltage transformer.

If an electric current is passed through a small number of “turns” of insulated wire, it creates a magnetic field around the conductors, and if they “link” with a large number of additional turns, you get a large voltage induced into the large number of turns. This is true of any transformer.

A “Tesla Coil” differs from a basic transformer in that it is “tuned” so that it resonates in order to produce an even bigger voltage with greater efficiency than a basic untuned transformer would do.

The tuning is a bit like tuning a string on a musical instrument - it makes a tiny bit of energy from a plectrum bow, hammer etc. produce a louder sound than the same energy would have done if it had been applied to the same string when left flat on a table and unsupported at the ends.

– Best wishes - Majikthise.