Afroman goes over the basics of how to use an operational amplifier to amplify tiny voltages, and builds a circuit to listen to very faint sounds with a microphone.

For more information about amplifiers, Google “inverting amplifier” “non-inverting amplifier” “instrumentation amplifier” “class A amplifier” “class B amplifier” “class AB amplifier” and that should give you a lot to chew on.


  1. I put this circuit together but I didn’t have the 5k resistor so I used a 1k resistor. But it didn’t work so I’ll try to find a 5k and test it out again.


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