Sometimes, I dabble with analog electronics, and notice how many basics I'm still lacking, how much intuition and debugging abilities...

I'm building a simple sawtooth oscillator, using a single transistor in "avalanche mode". Got the LED blinking! :) But as soon as I connect a sound system, the oscillation seems to collapse. Do I need a "buffer"? (I barely have any idea what I'm doing! :D)

This is based on, but using a 9 V power supply, and a PN2222A transistor, because that's what I had. It's like a weird puzzle to me, and I barely know where to start looking. Digital electronics seem so much more convenient! 😭

@blinry input of your sound system has too low impedance and is loading down the oscillator (you are also feeding DC into the audio equipment which isn't desirable).

Below is a link for the principle of buffer amplifiers so you know what the circuit looks like, you may be able to swipe a design from a similar project if you don't want to work out all the resistor values yourself (put a capacitor between the output and your sound system input, beware of polarity) >>

@vfrmedia Whoa, thank you! These are some really good pointers.

@blinry no problem - glad I could help (unfortunately I've also mostly been working with digital electronics and the test lab I normally use is 100km away from where I am currently, or I'd even try and make up the circuit myself..)

@blinry try putting a capacitor in series with the audio signal to only allow AC signal to get through. Maybe your audio input is supplying a DC voltage as needed by some microphones.

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