ABSTRACT
Pyroelectricity refers to electricity generated by a change in temperature; it can be used to sense temperature or heat sources (such as people). The direct piezoelectric effect refers to electricity generated by a stress; it can be used to sense a stress or a strain. The reverse piezoelectric effect refers to the generation of strain by an electric field, due to the effect of the electric field on the polarization. Polarization refers to the separation between the positive and negative charge centers of a material. The reverse piezoelectric effect is used for actuation. Sensing and actuation are basic functions of a typical smart structure, which responds to a stress or strain that it senses by providing actuation.
