Capacitive Thickness Gauges and Displacement Gauges: Frequently Asked Questions

The measurement surface of the VE series gap detector has a three-layer electrode structure consisting of a "measurement electrode," a "guard electrode," and a "sensor case," as shown in the diagram below. The "measurement electrode" is the electrode used to measure capacitance, and although it varies depending on the type, it is less than 1/3 of the sensor diameter. The "guard electrode" is an electrode that ensures the linearity of the sensor, and it guards against the electric field lines emanating from the measurement electrode spreading outwards. The red dotted line in the diagram represents the electric field lines emanating from the guard electrode. Thanks to this, the electric field lines shown in blue emanating from the measurement electrode can be directed straight towards the conductor, thus enabling highly accurate measurements with good linearity.