What's the function of buzzer?

Buzzer is mainly used as warning tone and alarm sound.

As an acoustic component with integrated structure,buzzer supplies power with DC voltage.And it is widely used in 

computer,printer,duplicator,alarmer,digital toy,car electronic device,telephone,stop watch,etc. and used as alarming

component.

In general, it's main function is reminding and alarming.With this function, it has lots of applications.