A high potential Tesla coil impulse generator for lecture demonstrations and science exhibitions

Demonstrations of high voltage phenomena are among the most spectacular and visually beautiful illustrations of physics. Here, we describe a high potential generator (several hundred thousand volts) which is based on a resonant transformer, derived from a standard Tesla coil arrangement with high Q secondary coil. Control electronics have been implemented that allow the user to command single shot discharges, should they be required for a particular demonstration. We review the behavior of a coupled resonant system with relevance to the spark-gap excited Tesla circuit implemented in our generator. The importance of the Q factor in the secondary coil design is emphasized, but only with due regard to other design factors including the coupling coefficient and primary spark-gap, which in certain configurations can outweigh the benefits of achieving very high Q.