For single-ended applications, the desired output is proportional to the absolute value of capacitance, whereas for differential capacitance
, the sensor consists of two capacitors that vary ratiometrically as the sensed quantity changes.
MEMS accelerometers generally operate on a deflection principle, in which a mass deflects closer to or away from an electrode, causing a differential capacitance
, he said.
The resulting relationships between electrostatic potential and surface energy (electrocapillary curves), surface charge, and differential capacitance
are completely consistent with the traditional sharp-interface models of electrochemical interfaces.
Typical pressure sensor technologies include differential capacitance
, piezoresistive or resonant silicon.