over-arc current are not too extreme...Vacuum capacitors use highly evacuated glass or ceramic chamber with concentric cylindrical electrodes....They are extremely low loss and used for high voltage high power RF applications, such as transmitters and induction heating.... http://en.wikipedia.org/wiki/Vacuum_variable_ capacitor http://en.wikipedia.org/wiki/Types_of_capacitor __________________ Live well.... Register to Reply Good Answer (Score 2) Go to