What is Electret Condenser Microphone?
The sensitivity range is - 54 to - 24 dB and the signal-to-noise ratio range is 56 to 72 DBA. Our electret condenser microphones also have operating voltages of 1.5, 2, 3 and 4.5 VDC and operating frequencies up to 20000 Hz, making them ideal for a variety of consumer and household electronics, medical equipment and industrial applications. Fbelec can also be customized. In order to deal with moisture and environmental pollutants, the protection grade of several ECM models also reaches IP67.
The electret microphone has two metal plates, One of the surfaces is coated with an electret film (mostly polyperfluoroethylene propylene) and ground it. The other plate is connected to the gate of the field effect transistor, and a diode is connected between the gate and the source. When the electret diaphragm itself has charge, the surface charge ground charge is Q, and the inter plate ground capacitance is C, the ground voltage U = q / C is generated on the electrode head. When the mechanical wave irradiates, the capacitance C changes, and the electric charge q remains unchanged, It will cause the change of voltage. The magnitude of voltage change reflects the strength of external sound pressure. The length of this voltage reflects the wavelength of external sound wave. This is the working principle of electret capsule microphone (ECM).
The diaphragm of electret microphone mostly adopts perfluoroethylene propylene, which has good humidity performance, generates more surface charges and is less affected by humidity. Because the microphone is also a capacitive structure, the signal internal resistance is very large. In order to lead out and amplify the voltage signal generated by sound wave, its output must also use field effect transistor.
