Original poster: Phlunktfysics101-at-aol-dot-com I'm trying to figure the correct dimensions of my coil on JAVATC. In the "PRIMARY" parameters section it asks for Primary Capacitor (uF). Does anybody know a formula to calculate this? I'm using 50' of 0.25" copper tubing coiled in flat spiral form with 1/2" spacing between turns, approx 11 turns. Thanks! Jack