Piezoelectric devices

The history of the discovery of piezoelectricity and its application in practical devices is traced from the late 19th century. The origin of the piezoelectric effect is outlined in terms of the symmetry of the materials, and Tables are given in which the electroelastic properties are listed for single crystals, ferroelectric ceramics and polymers which show the phenomenon. The applications of both the direct and inverse piezoelectric effect are considered in devices operating at frequencies from DC to greater than 100 GHz. Particular attention is paid to signal processing using piezoelectric substrates for surface acoustic waves, and to the use of quartz in crystal-controlled oscillators, but the whole range of devices from low frequency transducers, through acoustic and ultrasonic devices to VHF filters is discussed.