Bimorph actuators are made from a sandwiched pair of piezoelectric elements which can expand and contract in length. When used as a sensor,bending causes one side to go into tension and the other into compression, and having a response frequency in the audible range permits the bimorph element to be used as a high sensitivity sound sensor. When used as an actuator, an electrical input results in a bending force which can be used as a switching element in a wide range of applications