TL431 Oscillator

RE: TL431 Oscillator

DAB — Sun, 04 Oct 2020 19:15:02 GMT

Good project.

In my early electronics days, I spent a lot of time trying to make circuits not oscillate.

In Tech School we did the whole gambit using tubes.

Now if you want a real challenge, pick up some surplus tubes and set them up as a simple amplifier.

Lots of fun in the old days, many more issues to work around.

DAB

RE: TL431 Oscillator

dougw — Sun, 04 Oct 2020 14:19:17 GMT

Cool experiment. I've seen some transistor based Colpitts oscillators with very similar topologies. I wonder if this would work as is with a Darlington.

RE: TL431 Oscillator

jw0752 — Sun, 04 Oct 2020 06:42:13 GMT

Hi Jon,

I thought that was really cool. I have played with the TL431 a little but it never dawned on me that it could be an oscillator. Do you think we could make an LM 317 oscillate in a similar fashion? With an Amp and a half we could have some fun.

John

RE: TL431 Oscillator

shabaz — Sat, 03 Oct 2020 22:21:23 GMT

Hi Jon,

Very useful blog post. That's a significant amplitude oscillation! I'd also been wondering if a TL431 oscillator was possible, but the thought didn't occur to try to construct it into a Colpitt's oscillator. I wonder if this circuit could work for audio alert tones.

This might be the lowest cost and simplest single 3-pin active component based tone alert. Previously I'd tried a single-transistor oscillator connected to a 2-wire piezo, but it required a small transformer so that's a pain to construct the two windings. This TL431 oscillator is much easier to implement since it uses just a single inductor instead.

Also, the 555 chip, versatile as it is, is a pain to quickly assemble into hobby circuits when just a tone is required, due to the all the wiring that is needed across from one end of the chip to the other, to get it into the astable mode : )