The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com 15kV 60mA Bipolar Tesla Pancake Coil System   .004 mfd Doorknob Capacitor, 6 series 1/2" Tungsten Spark Gap 2 1/2 turns of 1" Copper Ribbon for the primaries  150 turns of magnet wire for the secondaries. Closeup of sparks... (C) Jeff Behary, 2007, 2008