I first saw a coil in 1976. A neighbor had built a coil that generated an arc that was about 2 inches long.
Tesla coils are strange devices - they shoot electricity off into the air.
Electricity is something that we rarely see - it usually stays imprisoned inside electrical wires, like a genie in a bottle. The 8.5-foot Tesla Coil I built the principal coil we use in Dr. MegaVolt performances in 1991 at UC Berkeley with the help of Paul O'Leary. In 1996 members of Survival Research Laboratory built a cage to protect a person from Tesla coil currents, and I got inside the cage as a stunt at a party at Christian Ristow's warehouse space. All the current flows on the outside of a conductor, isolating the interior from potentially dangerous electric fields. Eight months later I decided to shrink the cage down around my body and create a metal suit that would allow mobility.