Patent ID: 6530275
Filing Date: 2003-03-11
Classification: G01P

Abstract:
A sensor comprising:a first electrode; a first driver for providing a first periodic signal to the first electrodes; a second electrode; a second driver for providing a second periodic signal to the second electrode, the first and second periodic signals being 180Â° out of phase with respect to each other; a third electrode between and movable relative to the first and second electrodes, the first, second, and third electrodes forming a differential capacitor; signal processing circuitry including an amplifier coupled to the third electrode for providing an output signal that is fed back to the first driver and the second driver to change an amplitude of the first periodic signal and the second periodic signal in response to the third electrode moving, the change in the amplitude of the first periodic signal causing a change in the signal on the third electrode such that the third electrode has substantially no periodic component and so that the electrostatic force between the third electrode and the first electrode is substantially equal to the electrostatic force between the third electrode and the second electrode.