Electret microphone capsule schematic. wdwd [CC BY 3.0] The electret condenser microphone that I bought for pennies is a capacitor microphone, so why is there no high voltage supply? The answer ...

The ones in microphones ... electret detectable out to 10 inches. This was with the original wax recipe, but there are now much better materials available, like polyethylene. [Jay] heated a a ...