Three basic types of Pepperl + Fuchs capacitive sensors

The German Pepperl+Fuchs capacitive sensor is a device that converts the measured change into the capacitance change. It is a variable capacitor in itself. Because this sensor has the characteristics of simple structure, small size, good dynamic response, high sensitivity, high resolution, and non-contact measurement, it is widely used in displacement, acceleration, vibration, pressure, differential pressure, liquid level, etc. Sub-content and other testing areas. The principle, structure type, measuring circuit and engineering application of capacitive sensor. When the measured change causes any one of the parameters to change, the capacitance also changes accordingly, thus completing the conversion from the measured to the capacitance.

Pepperl+Fuchs capacitive sensors have three basic types:

Variable pole-pitch capacitive sensor, variable area capacitive sensor and variable dielectric constant capacitive sensor.

The measuring circuit of a capacitive sensor is a circuit that regards the capacitive sensor as a capacitance and converts it into voltage or other electric quantity. Therefore, the commonly used measurement circuits mainly include bridge circuits, frequency modulation circuits, pulse width control circuits, operational amplifier circuits, diode double-shaped AC bridges and ring diode charging and discharging methods. The frequency modulation circuit actually uses the capacitive sensor as a part of the oscillator resonant circuit. When the input quantity causes the capacitance to change, the oscillation frequency of the oscillator changes.