公开(公告)号：US4167697A

公开(公告)日：1979-09-11

申请号：US876602

申请日：1978-02-10

Applicant: Joseph P. Gerber

Inventor： Joseph P. Gerber

IPC: G01R17/12 ,  G01R27/26

CPC classification number: G01R27/2605

Abstract: An improved capacitive pick-off circuit is provided by utilizing an operational amplifier wherein a pick-off capacitor to be measured forms a part of a feedback circuit of the operational amplifier resulting in the gain of the operational amplifier becoming inversely proportional to the capacitance or directly proportional to the gap between the plates of the capacitor thereby providing a measure of capacitance. A differential capacitive pick-off circuit is implemented by using a pair of operational amplifiers wherein feedback circuits controlling the gain of the operational amplifiers include pick-off capacitors to be measured and a third differential amplifier is connected to the outputs of the two operational amplifiers to provide a signal representing the difference in capacitance between the two pick-off capacitors.

Abstract translation: 通过使用运算放大器来提供改进的电容式拾取电路，其中待测量的取样电容器形成运算放大器的反馈电路的一部分，导致运算放大器的增益与电容成反比或直接 与电容器的板之间的间隙成比例，从而提供电容的量度。 通过使用一对运算放大器来实现差分电容性拾取电路，其中控制运算放大器的增益的反馈电路包括要测量的拾取电容器，并且第三差分放大器连接到两个运算放大器的输出端 提供表示两个拾取电容器之间的电容差的信号。