A typical microphone has a diaphragm that is exposed to incident pressure waves. These pressure waves cause the diaphragm to deflect and this deflection is detected by various transduction mechanisms and converted into an electric signal. In a micro-electro-mechanical system (MEMS) microphone, conventional transduction mechanisms may include piezoelectric, piezoresistive, optical, and capacitive mechanisms. A simple MEMS microphone may be a capacitor consisting of a counter electrode, more commonly referred to as a “backplate”, and a diaphragm. When a voltage is applied across the backplate/diaphragm capacitive system, and sound waves cause the diaphragm to oscillate, the sound waves can be converted into useable electrical signals by measuring the change in capacitance caused by the movement of the diaphragm relative to the backplate. Many MEMS pressure sensors likewise employ the various transduction mechanisms discussed above to sense a change in atmospheric pressure.
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