What changed because of them
In 2009, on the Tesla Coil mailing list and 4hv.org, Hammer described a DRSSTC driver he called the Predikter: phase lead added to the feedback so the bridge switches slightly ahead of the current zero, letting large IGBTs reach soft switching despite their own turn-on time, plus a totem-pole anti-shoot-through gate stage of his own. Ward folded the phase-lead idea into UD2.1b as an adjustable inductor in the feedback network. Kaizer's phase-lead calculator for the UD2.x line is still named after it.
In November 2019 he released his QCW ramp generator because people kept asking for the code: an Arduino Pro Mini, five pots, two switches and a handful of passives, with the ramp leaving as filtered PWM on one fibre and the burst trigger on the other. Everybody should be able to build a QCW coil even if they cannot write code, he wrote, so here it is. Rafft built a record coil on it two years later.
Still active. The large dual-DRSSTC system he built with Kaizer Power Electronics opened at Energimuseet in April 2025.
Their boards
his own scope capture of the 12.8 ms ramp
Builds and boards on the tree
- The Predikter, phase-lead gate driver · 2009
- QCW ramp generator · Nov 2019
Sources
- pupman.com: the Predikter (28 Jun 2009)
- highvoltageforum.net: QCW ramp generator
- kaizerpowerelectronics.dk: Energimuseet system (2025)
Written from what Finn Hammer published, by one person, so it can be wrong in places. The page is meant to become editable, wiki-style, by profiles above a trust level. Until then, corrections go to the forum, and anything Finn Hammer asks to change or remove is changed the same day.