| 摘要 |
A very sensitive servosystem is provided for use with measuring instruments or gauges of the type wherein the force to be measured is counterbalanced by an identical force which tends to maintain the force sensing element in a null position. The restoring force may be current sensitive. Deviations from the null position are represented as an output of an alternating current bridge circuit. The bridge output is utilized in feedback circuit to control a current supplied to the gauge restoring force device. High resolution is accomplished by means of an amplified bridge output, a narrow band filter, and a phase-lock loop circuit. When used in association with a pressure gauge of the type described, the force and counter force are per unit area of sensing element.
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