MEMS and sensors

What is the typical way a MEMS microphone converts sound into an electrical signal?

  1. ADetecting the temperature change of a resistor heated by sound
  2. BDetecting the light output of an element that glows with sound
  3. CDetecting the change in capacitance between a membrane vibrated by sound pressure and a fixed electrode
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Answer: C. Detecting the change in capacitance between a membrane vibrated by sound pressure and a fixed electrode

A typical MEMS microphone forms a capacitor from a thin membrane (diaphragm) that vibrates with sound pressure and a perforated fixed electrode (backplate), converting the change in capacitance caused by the membrane's vibration into an electrical signal. It is small and easy to mass-produce, so it is widely used in smartphones.

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More MEMS and sensors questions

  1. How does the forward voltage of a silicon PN junction at constant current depend on temperature?
  2. What is the operating principle of the DMD (digital micromirror device) used in projectors?
  3. What is the general ink ejection method of inkjet printer heads made with MEMS technology?
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