Thursday, February 7, 2013

Variable Inverting to Non Inverting OP AMP amplifier

This is a pretty simple but useful circuit I put together.  It's basically a variable inverting/Non-inverting amplifier.  When the pot is all the way left, the signal is Non-inverted.  All the way right, it's inverter. the center has no output.  I designed the circuit to mimic a property on my State Variable Filter module. From I can tell, it works exactly the same.  I was surprised when I tried searching for an op amp set up that would do this, I couldn't find one.  I probably just don't know what its actually called.  Anyway, here's the design I came up with.
I used a 741 to test it out. 
In this video, I used it on my Filter with a triangle wave.  as you turn the knob, the signal attenuates all the way to 0, which is about center,  then it begins inverting 


  1. First visit to your blog, good work! Picked up some handy tips too! I've been playing with electronics for years but never really understood it till I read 'There Are No Electrons', by Ken Amdahl, I'd really recommend it, very different approach.

    1. I'll have to keep my eye out for that.

  2. I just learned how to make one of these yesterday! They're actually called 'attenuverters'. There's about a million different ways to make them.