Re: SSTC- feedback vs. none

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "K. C. Herrick" <kchdlh@xxxxxxx>

For the record, referring to my posted simulation circuit 
Half-br_res-pri.jpg, when I add Schottky diodes across the bipolar 
transistor base:collector junctions, change resistors R3 and R11 to 8 
ohms, and then add the same resistances in series with the Q5 and Q2 
collectors...I get perfect IGBT switching at the primary current 
zero-crossings.  The 4 resistors act to tweak turn-off & turn-on 
delays as appropriate.  The Schottkys reduce the delay in TX1 by a 
hundred ns or so but the ones whose model I happen to have (1N5711s) 
still exhibit 250 ns of turn-off time.

Even though this is only simulation, it's "food for thought".

KCH