The coil developed by Nikola Tesla - also called Tesla transformer - is based on the principle of resonant circuits of high frequency electromagnetic oscillations and produces visually perceptible energy which can be sent out freely into space in the form of series discharges from the secondary coil.
Günter Held and Mathias Betz succeeded in reproducing the series of experiments made by Nikola Tesla and will be presenting the results they have achieved from several years' work.