Testing the TK Tar Baby

[picowatt]

@PW: Yes, you are right and I agree with you totally, and I've got a more sophisticated design with a mosfet half-bridge, driven by gate driver chips and triggered by RF pickup in a CMOS inverter, that will likely blow the socks off this one, with true SGTC style long lightning bolts from the top capacity.

This coil is actually being used for a different purpose, which you might be seeing now. it's never going to make those long lightning bolt sparks, but when I have it working at full power with the straight, unconditioned gate pulses, however slow they are, it will be proving a point that I've been trying to drive home for years now, I think. And it will make a good audio-modulated demonstrator as well.

Don't worry... there are more and better SSTCs in my future. I have a nine-pound spool of that #27 magnet wire and I only used 1/4 pound for this coil, and I've been constructing a coil winder in my spare time. When I go to the trouble of using mosfet drivers and I expect the thing to run for a while, making lightning bolts, I'll use a full H-bridge and a PLL circuit, probably, with driver chips, of course. I have a few Intersil H-bridge driver chips right here, in fact, now that I think of it, HIP4080AIP. Thanks for reminding me, I had forgotten those were in there. I got them as _free samples_ from Intersil about ten years ago.

TK,

You do seem to have a "thing" for SSTC's.

PW

[Magluvin]

@Mags:
Yep, you've got it.




I've cut out the irrelevant components and noted the bias supply section in the following schematic. Notice anything interesting about the circuit? For example... why does it oscillate?

Thanks.

The transistor is triggered by the feedback looking loop, and in sync with the oscillations of the secondary?

Mags

[TinselKoala]

Thanks.

The transistor is triggered by the feedback looking loop, and in sync with the oscillations of the secondary?

Mags

Yes, sure... but...
I was hoping you would say, "For the same basic reason the NERD circuit oscillates."

[TinselKoala]

TK,

You do seem to have a "thing" for SSTC's.

PW

What else am I going to do with all that magnet wire?   

(I have a 2 kW rotary SGTC that is just too big and noisy to run in a house, so yes, I am trying to find the optimum small tabletop designs for demonstrations and general mayhem. I also have a smaller 75 W SGTC that I use for some elementary demonstrations, I'll dig it out one of these days and show it off. SGTCs are dangerous, though, because of the HV in the primary circuit. That's why I like the SSTCs, you can get spectacular results with just a few hundred volts in the primary.)

[TinselKoala]

26 volts DC input at just over 2 amps: Steady corona discharge from the NE2 wire.

The coil will light up a compact fluorescent bulb brightly at 18 inches away, wirelessly, running on 30 volts input.