Nature and use of piezoelectricity

Piezoelectricity means “pressure electricity.” It refers to those electrical effects produced when certain crystals are compressed, and conversely, to the deformation of crystals in an electric field. Several hundred different crystals have been found to be piezoelectric, but the only ones that are of present practical importance are natural crystals of quartz and tourmaline, and artificial crystals of Rochelle salt and ammonium phosphate. Important uses of these crystals are described.