LM386 OpAmp as an Oscillator

[Dan Dawson]

I found this pretty neat Instructable on turning the LM386, common place in making simple lo-fi amplifier, into a simple square wave oscillator. I put one together it only took about 30 minutes and I would suggest this to anyone who wants to get started or help anyone else get started in making simple sound circuits. By itself it sounds similar to the APC but more of a humming noise and less glitchy sound. Where I really see potential for this is replacing the clock source on some things and seeing what happens. Unfortunately I don't have an oscilloscope to hook this up to so it someone knows of any free software to use my computer to read signal waves please share. If anyone else decides to build one of these and has an oscilloscope please share a video.

I also came across this great PDF by Texas Instruments explaining how to make oscillators using op-amps. There are a few schematics for single, double and quad packaged op-amps, I am most excited to build the next to last one that has sine and cosine outputs also because it is called the Bubba Oscillator.

While using an amp as an oscillator isn't at all a new idea as somewhat of a noob to building my own components I have never really experimented with this technique. In the next few days I will be trying some different chips and components and just generally messing around trying to create a stable clock source from an opamp.

[Dan Dawson]

A little edit: the lm386 oscillator does not make square wave but very unstable sine waves, or atleast thats what my research has shown. So to make up for this I have found another example thats even simpler and produces a square wave that still unstable but can be stablized somehow I am sure. It is almost identical to the schematic from the previous osc.