Mechanism of active buzzer sound

Structure of piezoelectric diaphragm

The piezoelectric sound element must have a piezoelectric diaphragm.This structure is widely used in active buzzer,piezo active buzzer,sem buzzer.

This is a simple structure in which a piezoelectric ceramic adheres to brass or nickel alloy metal plate.

Mechanism of producing sound for piezo diaphragms

When a voltage is applied to the piezoelectric ceramic, it extends in its plane. When a voltage is applied to the piezoelectric diaphragm, since the metal plate is not stretched, it is bent as shown in (a). When the polarity of the applied voltage is reversed, the piezoelectric ceramic shrinks and the metal plate is bent toward the opposite side as shown in (b).

When the direction of the applied voltage alternates, the states of (a) and (b) are repeated, and as shown in (c), sound waves are generated in the air.

A piezoelectric system can be constructed for nearly any application for which any other sort of electromechanical transducer may be used. If combined with a normal electrodynamic woofer it can be created into a complete sound system. These kinds of devices are known as stack actuators, and they're employed in a range of specialty applications