Testing the TK Tar Baby

[TinselKoala]

@PW: no, not yet, the batteries I'm using are just about ready for Dim Bulb 2 and other circuit features are not yet stable enough for me to want to put in the sustained attention that a good time-temp-current profile will take. Besides, looking at the recent posts from RA, I think she's decompensating and getting further and further removed from reality and I'm feeling discouraged a bit.

Now... if I had a nice, paper chart recorder and a mile of chart paper, I could just sleep through the whole thing.

But I did purchase two more batteries, so now I have a matched set of 6 ea. 12 V nominal, 5 A-H sealed lead-acid batteries, so if voltage is the key, I can supply it, and if good randomised Dim Bulb repeats are necessary I can handle that too. I'm setting up right now to see if intercell lead inductance and another battery or two will bring my osc freqs down to the 1.5 MHz range.

[picowatt]

TK,

All I can say is, well, "geeeeesh..".  I now have a much greater understanding of certain "frustrations" I have noted in "other" threads. 

I am beginning to wonder how a few IRFPG50's would perform as a class A electrostatic driver amp amp.  It is beginning to sound like a better use for them.

I just wish they were not so slow, i.e., large Ciss.

PW 

[TinselKoala]

More data: with fewer than 30 Volts in the main supply, the oscillations (at least using the 555 timer) become less and less strong and more and more "picky" in terms of the 555 input power range needed to produce them, until they become difficult indeed to find at below 29 volts indicated in-circuit. Of course at less than 10 volts indicated each, these batteries could be considered completely flat.

Restarting with a full battery pack at 38.4 volts open-circuit, the oscs return in full force and controllability.

[TinselKoala]

TK,

All I can say is, well, "geeeeesh..".  I now have a much greater understanding of certain "frustrations" I have noted in "other" threads. 

I am beginning to wonder how a few IRFPG50's would perform as a class A electrostatic driver amp amp.  It is beginning to sound like a better use for them.

I just wish they were not so slow, i.e., large Ciss.

PW

Frustration isn't the half of it. It was the same three years ago on Naked Scientists only not so much with builders. The threads there are still archived. And it was the same two years ago with the Energetic Forum (panacea u.) And it was the same last year here and on .99's forum. And it's the same now.

Yeah, you really have to pump them power hexfets to wake them up. In my next SSTC I'll use these, and discharge a tantalum cap into the gates via a phase transformer. That'll kick start those puppies, I'll bet.

Something like this but more better.
http://www.youtube.com/watch?v=HQfR-wsDoBI

[TinselKoala]

This shot is more typical of the scope shots RA usually tries to show. She's been doing this kind of stuff for years. The few other shots in the papers are the only really informative shots she's ever posted, as far as I can tell. Usually they are a mess of false triggering, aliasing, and continuous combs all across the screen, like this silly, improperly triggered, useless for anything shot here. I swear, if misuse of an oscilloscope is a crime, these people are the Moriartys of South Africa.

Paper 1, Figure 8: