MEMS and sensors

What is the principle by which a capacitive MEMS accelerometer detects acceleration?

  1. AChange in resistance due to temperature change
  2. BChange in capacitance between electrodes caused by displacement of a movable mass
  3. CChange in optical interference fringes
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Answer: B. Change in capacitance between electrodes caused by displacement of a movable mass

When acceleration is applied, a movable mass supported by springs moves due to inertia, changing its distance from fixed electrodes. The resulting change in capacitance is detected by a circuit to determine the acceleration. The structure is simple and low-power, so it is widely used in smartphones.

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More MEMS and sensors questions

  1. What is the purpose of sacrificial-layer etching in MEMS fabrication?
  2. Which correctly describes the piezoresistive effect used in semiconductor pressure sensors?
  3. What does a sensor using the Hall effect (Hall element) mainly detect?
  4. Which force does a vibratory MEMS gyroscope use to detect angular velocity?
  5. Which correctly describes deep RIE (the Bosch process) used in MEMS fabrication?