[sdiy] trying to understand amplification of an electret mic element

[Ingo Debus]

Am 06.09.2011 um 22:47 schrieb dan snazelle:

> switching the cap to a 10uf as Ingo suggested, and using an  inverting instead of non-inverting  amplifier made a WORLD of difference.
> 
> I can now get giant gains with just one opamp.

Ah, sorry, I thought you were using an inverting amplifier in the first place.
A non-inverting amp already has a very high input impedance. Did you just connect the cap and nothing else to the non-inverting input of the opamp? Maybe this was the problem. With a high value resistor (1 Meg or so) from the non-inverting input to ground maybe it would have worked even with the small cap. Usually opamps don't like it if there's no DC path from their inputs to anywhere.

Ingo