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30 or 40 transistors die in reverse biased avalanche breakdown catastrophe. You told me not to put components into a live circuit, and on this occasion, you were right. Also, some clever 1-transistor oscillators ๐Ÿ™‚

By Julian

Youtuber, shed dweller, solar charge controller aficionado

15 thoughts on “Transistor avalanche disaster”
  1. Avataaar/Circle Created with python_avatars Ninja warrior says:

    Why do you use 19volt battery for it?

  2. Avataaar/Circle Created with python_avatars Tinkerbot says:

    Surely the capacitor is at 18V potential even without the LED in circuit? After all, one plate is connected to Vcc and even if the other plate is floating, it is still at a lower potential than the +ve plate and so 18V would be dumped through the transistor as soon as you put it in circuit.

    I'm obviously missing something, but what?

  3. Avataaar/Circle Created with python_avatars Filmaker25 says:

    why is this a "disaster?"

  4. Avataaar/Circle Created with python_avatars TZE VEN POH says:

    I think it is a bad idea to put a 4.7uF across CE of the transistor. You should move the capacitor leg on the Collector to the GND instead. This will allow the energy stored in the capacitor to be discharged through the LED as well, instead of just wasting it. I suggest using smaller capacitance value (and increase the resistance value to maintain the oscillation period) to reduce the stress on the transistor. Alternatively, put a small resistor in series with the transistor to limit the charge dumping current.

  5. Avataaar/Circle Created with python_avatars Ricardo Calles says:

    The avalanche mode works great but you have to provide a low resistance load in parallel to the transistor CE junction for the capacitor to discharge through.

  6. Avataaar/Circle Created with python_avatars ็Ž‹้œ‡ says:

    I found a book called Triggering of Avalanche Transistor Pulse Circuits, can anyone help me find the PDF version, thank you very much!!!!!!!!!!!!!!!!!!!!

  7. Avataaar/Circle Created with python_avatars James King says:

    This video is like using a Varvatos diode. Best just to use one of those. You don't need as high of voltage.

  8. Avataaar/Circle Created with python_avatars James King says:

    High Value resistor from C 2 E no need to move LED. Then change the capacitor to vary your osc frequency.

  9. Avataaar/Circle Created with python_avatars andymouse123 says:

    I'd forgotten how cool all of the oscillators sound together !

  10. Avataaar/Circle Created with python_avatars lucas arjona says:

    Thanks for sharing your knowledge. ๐Ÿ‘๐Ÿป๐Ÿ‘๐Ÿป

  11. Avataaar/Circle Created with python_avatars Adrian Finn says:

    It sounded like some music out of an 80's horror movie.

  12. Avataaar/Circle Created with python_avatars Sebastian Andreas Gruber-Kersting says:

    History will remember you as a crude transistor killer!
    …hehe…

  13. Avataaar/Circle Created with python_avatars Fluxnet Games says:

    this brings me back to my college days, and somehow someway the frequency of the red LED made one of my eyes twitch lmao.

  14. Avataaar/Circle Created with python_avatars KaxLon says:

    Sounds like you get binaural tones. =)

  15. Avataaar/Circle Created with python_avatars Jerry Ericsson says:

    Have you had any trouble with those little headphone jack adapter plugs? Just wondering, I had 5 of them, and when I decided to re-use one, it all went to hell. The traces lifted off the board (using my soldering iron set at 245C.) I am still using them, however I rewired them and did not use the traces's at all, but instead ran some solid core copper wire (recoverd telephone inside house wire) from the pins to the 3 exposed connections. This works OK, but I am now searching for a more stable jack. The ones I had were made of pressed paper, and even that is separating. Perhaps they are made for a one time use and I am expecting to much of the little gadgets.

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