Circuit increasing accuracy of AC sensors - removes inactive component of signal using comparator and phase shift network

摘要

An electronic circuit measures the values given by an a.c. measuring sensor operating at frequencies up to 4000 Herz. The circuit corrects for errors which occur with long cable lengths. Quadrature is removed by passing the signal through a comparator and phase shift network and comparing the output against a square wave in phase with the a.c. voltage source. A measuring sensor (1) determining the conductivity of a liq. is fed via a long, two-lead cable (2) with sinusoidal a.c. (3). The latter (3) is also fed to a phase shift network consisting of a capacitor (4) and resistors (5, 6).