Don Klipstein's page on solid-state coils was archived in August 1999 and is still up. Its theory section opens with a date: “I actually made working solid-state Tesla coils this way as long ago as 1978 and did not know then the whole reason why this worked.” The circuit is a single power transistor, a 2N3055 or something better on a decent heatsink. It oscillates on a tapped coil, with the upper half as the primary and the lower half as the feedback winding. The secondary is loosely coupled on purpose, so its stray capacitance series-resonates with the leakage inductance, and that gives the voltage gain. The secondary was one layer of 32 or 33 gauge magnet wire on an oatmeal box. The supply was no more than 40 V, since anything higher usually burned out the transistor, and he suggests unfiltered DC to halve the abuse. He got around 50 kV peak and sparks over 2 in, with very spectacular corona. Jim Mitchell named him to the Tesla list in June 2004, when Dan McCauley asked for the history of these coils. The 1978 date is his own recollection. The archived page is the documented record.
Sources
- Internet Archive: Don Klipstein, solid state Tesla coils (19 Aug 1999)
- donklipstein.com: the same page today
- pupman.com: Jim Mitchell, 9 Jun 2004
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.