Design of Signal Detection Circuit for Electrostatic Coupled Fringing Electric Field Sensor

A new type of oil sensor with electrostatic induction coupled fringing electric field effect is designed to solve the problem of oil monitoring accuracy influenced by the oil medium and the oil temperature. According to the oil environment requirement of aeroengine, the corresponding signal detection circuit with high-frequency anti-interference characteristics is optimized and improved. The circuit can not only be used to detect the low-frequency charge signal of electrostatic induction, but also detect the fringing capacitance signal under high-frequency excitation at the same time, obtain the change of the dielectric constant of aircraft engine tubing, and realize the synchronous acquisition of multi-dimensional data. The results of Multisim simulation show that the designed detection circuit can be stably applied to MHz high frequency excitation condition, and can accurately detect the small capacitance change of pF level. It solves the problems of unstable output and extreme distortion in the general detection circuit.