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Re: Solid state TC working! But.. (fwd)

List owner wrote:
> 
> ---------- Forwarded message ----------
> Date: Mon, 3 Mar 1997 10:18:27 -0700
> From: Jeff Detweiler <jd231825-at-engr.colostate.edu>
> To: tesla-at-pupman-dot-com
> Subject: Solid state TC working! But..
> 
> Greetings everyone,
> 
> I've been building Duane Bylund's solid state TC featured in the Sept.'91
> issue of Radio-Electronics, and I finally have it working! The secondary is
> 800 turns of 30 AWG wound on a 5-gallon bucket (yes, a 5-gallon bucket!)
> base-driven directly by the TC circuit. I got things hooked up just enough
> to see if it works, and I get a nice 4-5" discharge from just the bare wire
> in the air--haven't had time to make a discharge toroid yet. Duane Bylund
> was kind enough to send me some photos of this exact setup producing as
> long as 12" sparks, so at least I know what to aim for! I posted the
> circuit schematic at the following website and also will send it to Chip:
> 
> http://www.engr.colostate.edu/~jd231825/tesla/schematic.gif
> 
> OK, here's the catch. The circuit drives a hand-wound ferrite core
> transformer T2 (see schematic) that hooks directly to the secondary ala
> magnifier fashion, but I would like to be able to interchange this
> transformer with a flyback transformer to drive a large plasma globe I have
> already built. T2 has a 10 turn primary, so I hand wound 10 turns around
> this hefty flyback transformer I have (an older one rated for 25 kV or so)
> and hooked it up.
> 
> When I turned up the juice with my variac, I got absolutely no output from
> the flyback transformer at first. As I varied the frequency of the circuit,
> I hit a "resonant" frequency of the flyback somewhere around 100 khz and
> the transformer went from dead to producing a crackling 3" output
> discharge. But it remained practically dead for all other frequencies.
> Also, the spark output at the resonant freq. was the kind of crackling,
> pulsed type spark you might expect from a capacitive-discharge TC, but not
> the continuous, rather smooth spark I am used to getting from a flyback
> transformer. Also, I should mention that I replaced D1 with a full-bridge
> rectifier for this experiment so that the power transistors Q3 and Q4 have
> continuous 160 VDC power, so I would expect continuous output from the
> flyback.
> 
> Question is, is this circuit feasible for driving a flyback, and if so, how
> should I go about it? Anybody have a good explanation for what is
> happening? All comments and suggestions would be greatly appreciated! Also,
> I just wanted to thank Malcolm and Bert Hickman again for all their help
> already.
> 
> Jeff Detweiler