Capacitive distance sensor

Details Capacitive distance sensor Capacitive distance sensor

1998-03-09

2000-09-05

Brown, Glenn W.

Electricity: measuring and testing

Impedance, admittance or other quantities representative of...

Lumped type parameters

324661, 324671, 324686, G01R 2726

Patent

active

061148628

ABSTRACT:
A distance sensor has a capacitive element in turn having a first capacitor plate which is positioned facing a second capacitor plate whose distance is to be measured. In the case of fingerprinting, the second capacitor plate is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.

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