Recent s.s.t.c. work...more-or-less

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

Greetings, all-

Increase in age & decrease in smarts is catching up with me but I 
press ahead haltingly (tho should have quit years ago).  I've 
repeated a fundamental mistake I made in my 1st-&-only working coil, 
now sadly defunct: I've neglected to shield the 5V-portion of my 
current electronics.  So...I'll have to saw apart the ckt board & put 
the 5V part in a box.

In the interim (to be extended shortly by a month away in Europe), 
I've frittered away some more time simulating 2 types of feedback, 
represented in

http://hot-streamer.com/temp/feedback2.jpg
and
http://hot-streamer.com/temp/feedback3.jpg

The circuits are essentially the same, incorporating a tuned primary, 
except that one employs feedback (to sustain the oscillation) from 
the secondary's current and the other, from a (simulated1-turn) 
pickup coil near the secondary.

Simulation yields the expected "notches" (or rather, one of them) for 
the case where feedback is taken from the extra coil -- but no 
notches when it is taken from the secondary-return.  Also, in the 
latter case, spark voltage (and hence power in) is much larger.

Notice that I simulate the spark with the 100K/10 pF switched-load at 
the right in each drawing, producing  waveform-dips at 50 and 90 us 
respectively.  Also, I need a small noise (100 KHz) source to get 
oscillation going -- V1 in each case.  And lastly, both waveforms are 
at "Probe 1 - NODE" but one happens to be labeled as at S2-N which is 
the same node.

So...  The phase between driving current & voltage is not shifting 
for secondary-return feedback (because there are no notches--& also, 
I checked the simulation waveforms) but it does shift, hence making 
near-zero-current switching difficult or impossible, in the other case.

Is this of any significance to solid-staters?  Can I tweak these 
circuits for more realistic simulation?

I'll be checking the List periodically while I'm away.

Ken Herrick