Unamplified Electret Microphone

Description

Designed for use in computer and radio compatible headsets this microphone is recommended for quieter applications because it is more sensitive and will pick up very clearly. The mic is noise cancelling by physical design so the mic should be placed in front of the speakers mouth to be heard distinctively.

How does an electret mic work?

The term electret is a combination word shortened from the two words ‘electrostatic’ and ‘magnet’. It’s constructed typically of a thin film that has magnetic particles embedded in it that have been aligned in a magnetic field while the film was hot and liquid material. When the material was cooled the magnetic particles were then electrically ‘stuck’ or ‘static’ in that magnetic alignment caused by the magnetic field they were exposed to. The electrostatic magnetic film is then used to create a diaphragm on the microphone capsule that will move when exposed to sound. The arrangement of the diaphragm is such that it creates a capacitive structure in the mic capsule. Because the electret film is magnetic it changes the capacitance of the capsule when it moves. That change in capacitance causes enough electrical signal to have an effect on the transistor gate that is also inside the capsule. The transistor is a built in pre-amplifier. Then the signal can be further amplified either inside the mic element or by whatever equipment the headset with that mic is eventually plugged into.