What is a buzzer?
A buzzer or better known as a buzzer is a small transducer capable of converting electrical energy into sound. To make them work, just connect the positive with the + and the earth or negative with the – of a battery or any direct current source.
How does buzzer work?
The operation is based on the piezoelectric effect of the materials. This effect works in such a way that when we apply a voltage the volume of the material changes slightly. The buzzers are built with two small plates, a metal and a ceramic, which take advantage of this effect but only generate a click since the materials changed shape but do not return to their natural state until the voltage is removed.
In order for a continuous sound to be emitted the plates need to vibrate constantly, for that an oscillator is installed that makes the materials change their state over and over again, and thus they can change thousands of times in order to achieve perceptible audio.
We can also find another type of buzzer (electromagnetic) that exchanges materials for 1 permanent magnet and 1 coil. When the coil receives electricity it causes the sheet metal to vibrate.
Despite the fact that all these devices at first glance all look the same, there is a great difference in their operation and they can be classified into 2 different types: electromagnetic and piezoelectric.
Within the piezoelectric we can find 2 types:
No Oscillator: Requires a voltage and an external oscillator to function
With oscillator: They have an internal oscillator which facilitates operation since it is only a matter of applying voltage.
These devices are primarily used for alarms and sound controls with a small frequency range, such as in household appliances.