ABSTRACT

Piezoelectric materials convert mechanical energy to electrical energy (direct piezoelectric effect) and electrical energy to mechanical energy (indirect piezoelectric effect).

In the direct piezoelectric effect, the input is mechanical energy and the output is electrical energy. Mechanical input can be in the form of external stress (X) or strain (x). Electrical output is in the form of surface charge density (D or P), electric eld (E), or voltage (V) (Figure 2.1).