MEMS Microphone basics | MEMS microphone operation,working,advantages
This page covers MEMS Microphone basics and mentions working operation of MEMS Microphone. It mentions advantages of MEMS microphone over conventional microphone. The links to microphone vs loudspeaker etc. related to microphone are also mentioned.
The transducer device which converts acoustic signal into electrical signal is known as microphone. They can be processed in audio chain of the hearing aid. There are various technologies used for acoustic to electrical signal conversion. Out of these, condenser microphone is very accurate and smallest technology. Condenser microphone uses diaphragm which moves according to application of acoustic signal and this motion results into change in capacitance which produces electrical signal.
• Acoustic signal➨movement➨change in capacitance➨electrical signal
About MEMS Microphone:
MEMS stands for Micro-Electro Machanical Systems. The silicon technology has been advanced in recent years. The microphone developed using MEMS technology is known as MEMS microphone. They have become very popular in hearing aid industry due to reduced power consumption and noise levels recently.
MEMS Microphone operation | MEMS Microphone Working
The figure-1 depicts cross section of MEMS Microphone. Let us understand working operation of it. As shown it consists of flexible diaphragm and backplate fabricated on wafer of silicon. Diaphragm is constructed such that it moves based on sound pressure. The structure is designed which resembles variable capacitor. The fixed charge is applied between diaphragm and backplate in this MEMS microphone.
When sound pressure is being subjected to this microphone, it causes diaphragm to move which is proportional to amplitude of waves. This movement results into variation in the distance between backplate and diaphragm. This causes variation in the capacitance. With contant charge applied to the microphone, change in capacitance is converted into electrical signal accordingly. Capacitance value is reduced due to compression waves while it is increased due to rarefaction waves.
MEMS Microphone advantages
Following are the benefits or advantages of MEMS Microphone:
• ultra-small fabrication geometries
• low power consumption
• excellent stability
• low noise levels
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