Article Details

Abstract

Aiming at the problems of small capacitance and weak output signal of miniaturized capacitive torque sensors, this paper designs an instrumentation three-operational amplifier micro-capacitance detection circuit based on a ring diode bridge structure. This circuit takes the ring diode bridge as the core, and is combined with a transimpedance amplifier and a three-op amp instrumentation amplifier to convert capacitance changes into voltage signals. The circuit effectively suppresses common-mode interference and improves the signal-to-noise ratio. The experimental results show that the sensitivity of the detection circuit is 21.6 mV/pF, a capacitance resolution of 0.1 pF can be achieved, and the nonlinear error is less than 0.3% FS.

Keywords

torque sensor; micro-capacitance detection; ring diode bridge; instrumentation three-op amp

References

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About the authors

Liu Pengcheng (1999-), male, Han ethnicity, from Chengdu, Sichuan, is currently pursuing a master's degree in embedded systems and intelligent instruments; Gao Zhonghua (1972-), male, Han ethnicity, from Qiqihar, Heilongjiang Province, is a senior engineer and doctoral student. His research interests include precision instruments, machinery, and intelligent sensors.