Patent ID: 6877382

Claim:
A detector providing an electrical signal in response to a predetermined pressure difference comprised of: a. a diaphragm responsive to said predetermined pressure difference and a pair of electrodes, fixed in planar form, cooperating with and facing said diaphragm; b. an insulator sandwiched between and contiguous with said diaphragm and said electrodes; c. an oscillator having a frequency responsive to a capacitance between said electrodes, a monostable multivibrator responsive to said oscillator, and an integrator averaging a waveform from said monostable multivibrator to provide a feedback voltage; d. a feedback means applying said feedback voltage across said diaphragm and said electrodes whereby electrostatic forces upon said diaphragm maintain said capacitance substantially constant; e. a comparator means providing an electrical output signal when said feedback voltage exceeds a predetermined value; f. a secondary feedback voltage means controlling said integrator during reversed pressure conditions.