The output capacitance of a MOSFET is voltage dependent; therefore a single point measurement does not accurately represent the capacitance characteristic of the device. Curve fitting can be used to ...

[Jonathan Nethercott] does an excellent job explaining a capacitance test circuit which uses a reference capacitor to calculate the unknown capacitance.

In the sensor capacitance calculation, it is assumed that the capacitive sensing circuit is linear over the entire range of sensor. But these circuits are meant for user interface applications where ...