Lidmotor's Penny circuit help needed.

[TinselKoala]

Another thing: Looking at the specs for the BC337 and comparing to the 2n2222 I don't see much difference except in the voltage handling ability. What happens when you take the exact circuit you show above, with scope settings exactly as you have there, if you change the transistor to a 2n2222, or a 2n2369a, or MPSA18, my personal low-voltage favorite?

I'm asking because I don't have a BC337 on hand, and am not likely to be able to get one.

[Dark Alchemist]

Another thing: Looking at the specs for the BC337 and comparing to the 2n2222 I don't see much difference except in the voltage handling ability. What happens when you take the exact circuit you show above, with scope settings exactly as you have there, if you change the transistor to a 2n2222, or a 2n2369a, or MPSA18, my personal low-voltage favorite?

I'm asking because I don't have a BC337 on hand, and am not likely to be able to get one.

I literally have a crap load of BC337, lol.  Let me run the sim with a 2n2222 using my changes as Lidmotor's original design would not oscillate.

As far as a current probe in the sim I do not have that but I do have a probe that just spits numbers at you but someone mentioned that wouldn't tell me anything.


Nope, the 2n2222, 2n2369a, or the MPSA18 will oscillate.

[Dark Alchemist]

Using your suggestions.

[TinselKoala]

OK, so by setting the trigger as I suggested, the Blue trace vanished? You made no other changes, just setting the trigger?

Now try changing the timebase to 10 or 50 microseconds per division, making no other changes.

In your last post you said,

Nope, the 2n2222, 2n2369a, or the MPSA18 will oscillate.

So I'm confused again. The "nope" part doesn't seem to agree with the "will oscillate" part. Did you mean that "neither" will oscillate, or that they "will not oscillate" or what?
If they _do_ oscillate could you please post a scopeshot using one of them? If they don't oscillate, never mind, just please try the timebase change I suggested above.

ETA: Wait I see you have the "Blue" channel disconnected. Please go step-by-step. Replace your 0.1 ohm resistor, use the Blue channel to monitor the voltage just as you had in your previous shot. Change ONLY the trigger setting, to +0.25V on the Red channel, set to "auto" or "normal".  Then show the screenshot.
Then, change the timebase from 1 us/div to 10 or 50 us/div and show the screenshot. Please only change one thing at a time, because I confuse easily.

[TinselKoala]

I just checked the JT I showed in the video above. It oscillates at about 14.6 kHz, much much slower than the 3.76 MHz of the Blue trace you showed above. I'm not convinced that your Blue trace really is showing the main JT oscillation of your circuit, nor is the Red trace in your latest scopeshot.

Try this: using the exact setup you have just above, with only the Red Channel A Q1 collector signal shown. Set the trigger on Ch A, rising slope, +0.25 volts, "Auto" or "normal". Now change the timebase in steps. You are showing 1 us/div already, so now look at the signal at 10 us/div, 50 us/div, and 100 us/div, or whatever similar settings your scope allows.