What is a piezo audible alarm and how does it work?
Piezoelectric audible alarms are alarms that use very efficient piezo crystal wafers that have been bonded to a metal disk. When voltage is applied to the piezo wafer it deforms in proportion to the voltage applied. If an electronic signal in the audible hearing range is applied to this crystalline wafer the metallic disk will vibrate at this audible frequency. The sound pressure produced by this disk is very low without using the resonant properties of a tuned cavity (alarm body, or case) to boost this small signal. The use of an efficient piezo crystal, coupled with a specially tuned body, produces a high output alarm that consumes very little current.
