Electret Microphone Circuit

The diaphragm is made of thin teflon material and is also termed as electret and hence the name electret mic.

Electret microphone circuit.

This electret has a fixed charge c and is embedded between the two electrodes. Electret microphones can be inserted in the same box with the amplifier it only need 5 to 10v or 9v battery with a current consumption of just 1 5ma. An electret is a stable dielectric material with a permanently embedded static electric dipole moment which due to the high resistance and chemical stability of the material will not decay for hundreds of years. An electret microphone mainly consists of a diaphragm a couple of electrodes and an in built jfet.

This is the basic electret microphone powering circuit which you can use as generic reference when receivign circuits which use electret microphones. 2 the test circuit for an electret microphone the electret microphone jfet amplifier has the gate connected to a pick up plate which is pushed back and forth by the air the source is connected to the ground and the drain is connected to the output pin. An electret microphone is a type of electrostatic capacitor based microphone which eliminates the need for a polarizing power supply by using a permanently charged material. The circuit starts with the electret microphone.

How electret microphones work. This electret microphone in particular needs 2 2v of power in order to operate. The electret microphone test circuit schematic is shown below. As stated the microphone needs power in order to operate.

Since the microphone port of a computer provides about 2 3v of power this will perfectly power the electret microphone. If you leave out r2 the output impedance is roughly the resistance of r2.