How do piezoelectric buzzers work?

A piezo buzzer is a sound producing device.

The main working principle is based on the theory that, whenever an electric potential is applied across a piezoelectric material, a pressure variation is generated. A piezo buzzerconsists of piezo crystals in between two conductors.

When a potential difference is applied across these crystals, they push one conductor and pull the other conductor by their internal property. The continuous pull and push action generates a sharp sound wave.

Piezo buzzers generates a loud & sharp sound. So,they are typically used as a alarm circuits. Also they are used to make an alert of an event, signal or sensor input. A special characteristics of piezo buzzer is,the sound pitch or level is not depended on the voltage level that is, it works only in a specific voltage range.

Typically, a piezo buzzer produce can generate a sound in the range of 2 to 4 kHz