Original poster: "Mccauley, Daniel H by way of Terry Fritz <teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com> Anyone have any information on how to calculate the E-field (approximately) of a tesla coil. I saw an old post that stated Terry had an E-Field calculator program, but i didn't see one on the hot-streamer site. Any help appreciated. Thanks Dan