MEMS Single Axis Accelerometers

MEMS Single Axis Accelerometers

Micro Electro-Mechanical System, or MEMS Accelerometers, utilise two main types of technology, capacitive and piezoresistive. In a capacitive MEMS accelerometer, a suspended mass is displaced during acceleration events, moving it closer to or further from a pair of capacitive plates. The resulting change in capacitance is measured and converted into an output signal proportional to the sensor’s acceleration. Due to the displacement of the mass caused by gravity, an axis aligned normal to the local gravitational force vector will continuously read 1g. Piezoresistive accelerometers work through the displacement of a strain gauged cantilever beam. As an acceleration event occurs the beam deforms, putting the silicon gauges in a state of compression or tension. This in turn changes the resistance of the gauges and this change in resistance can be converted into a millivolt output signal through the use of a Wheatstone Bridge. Due to the wide dynamic response range the accelerometers can work at, they are the preferred choice in high impact tests.

DC Response Accelerometers Overview