The capacitance is directly proportionai to the area, A of the plates. Thus the capacitan.ce changes linearly with change in area of plates. Hence this type of capacitive transducer is useful for measurement of moderate to large displacements say from 1 mm to several em. The elementary diagrams of two types of capacitive transducers are shown in figure 4.13 (a) & 4.13 (b). The area changes linearly with displacement and also the capacitance. Figure 4.13 shows·

the variation of capacitance.