Piezoelectric switch

Patent Granted A piezo switch is an electrical switch based on the piezoelectric effect. The charge generated by the piezoelectric element in the switch is typically used to turn on an integrated semiconductor device such as a field effect transistor (FET), causing the switch assembly's output to be active, or "on". When the FET is on, current can flow through it as with a conventional metal contact-based switch. After the voltage pulse is dissipated in the gate resistor, the FET turns back "off", its normal high impedance state. The piezoelectric effect uses the fact that force applied to certain materials causes stresses that generate this electric charge. In the case of piezo switches, the force could be compressive pressure that causes the (typically disc-shaped) piezo element to bend very slightly like a drumhead.