Displacement transducers based on capacitive effects. The principle of a capacitive displacement transducer.
All capacitive displacement transducers operate on the principle of a capacitor, which is formed by two plates separated by a dielectric. Changing the size of the plates, the distance between them, or between them and the dielectric changes the capacitance.
Figure 1 shows the principle of a capacitive displacement transducer. It capacitance changes due to the movement of one plate relative to the other (Fig. 1 a), changes in the area of overlapping plates (Fig. 1, b), or move the dielectric (Fig. 1, в).
Known as the design, in which the dielectric, remaining stationary, changes its characteristics.
Based on this principle capacitive proximity sensor and capacitive switch approach that can detect target at a distance from the device. The same principle is laid down in a capacitive liquid level transmitter, where the change of the liquid level varies dielectric constant.