How are the sparks from a Tesla Coil different from sparks caused by static electricity generators or lightning?
Static electricity generators and thunderstorm clouds cause large amounts of electric charge to build up in one area, and an opposite charge to build up in another area. If the voltage rises sufficiently high, a spark will jump between these two areas. The spark will generally last only a fraction of a second. In contrast, the output from a Tesla Coil actually oscillates between a positive and negative voltage very rapidly (usually hundreds of thousands of times per second). More precisely, the output from most Tesla Coils is actually off the majority of the time, with several hundred short periods per second where the electricity is oscillating as described in the previous sentence. Because of the large number of pulses each second, the arcs from Tesla Coils usually appear to continuously flow out from the device.
