Capacitive edge sensor

Disclosed is a capacitive edge sensor. A conventional capacitor sensor has the disadvantages of non-linear output, quite great influences exerted by parasitic capacitance and distributive capacitance on the sensitivity and measuring precision, quite complex connection circuit, incapability of measuring the micro distance between two optical mirror surfaces which are spliced together or in parallel arrangement in Fabry-Perot and splicing mirror surface technologies, and the like. The capacitive edge sensor comprises a signal generation circuit (1). The signal generation circuit is respectively connected with a to-be-detected plate capacitor A (2), a to-be-detected plate capacitor B (3) and an amplitude limit circuit (4); a signal application circuit (5) is respectively connected with the to-be-detected plate capacitor A, the to-be-detected plate capacitor B and a low pass filter circuit (6); the low pass filter circuit is connected with the amplitude limit circuit; the amplitude limit circuit is connected with