Electronic – Do electret condenser microphones require phantom power


I was under the assumption that electret microphone capsules do not require any phantom power an can be connected in the same way dynamic microphone capsules can be, due to the fact that they contain a small permanent static charge built in. I am trying to build a really simple mic to hook up to my computer via the 3.5mm mic jack, and after wiring everything up, it doesn't seem to be working. Is this because there is in fact supposed to be some sort of phantom power circuit, or should I just double and triple check my wiring again?

Best Answer

Electrets don't need phantom power for the diaphragm, but the small capsules usually have a FET buffer inside which needs bias voltage. This can of course be derived from a phantom power source if necessary.

Here is a typical electret circuit:

Electret circuit

The value of the resistor is usually between 2k and 10k (cap say 10uF or higher) The datasheet for your capsule will probably give recommended operating conditions.

Here's a good link on simple electret circuits.
Another page with some more advanced ideas.