What is the passive buzzer?

passive buzzer is based on the principle of piezoelectric effect sound. Piezoelectric materials are generally used as piezoelectric ceramics. This material is used because, in particular, when a voltage is applied to the piezoelectric material, it will produce mechanical deformation with changes in voltage and frequency. Also, when the piezoelectric ceramic vibrates, an electric charge is generated. That is to say, this material can transform mechanical deformation and electric charge into each other. The vibrating plate in the piezoelectric buzzer is piezoelectric ceramic. Therefore, in order to make it vibrate, in addition to the piezoelectric ceramic itself, a voltage having an appropriate magnitude and frequency change is required to act on the piezoelectric ceramic. The piezoelectric (active) buzzer has a multivibrator inside, which can generate a voltage signal of 1.5-2.5 kHz. Therefore, the piezoelectric buzzer can sound.

In fact, the working principle of a passive buzzer is the same as that of a speaker. When using a square wave signal source to drive, a diode should be connected in reverse parallel, which can prevent the high-voltage back electromotive force generated during sudden power failure from penetrating other components, thereby shortening the life.

In contrast, the active buzzer is often more expensive than the passive buzzer, because there are many oscillation circuits, only need to connect the DC with the rated voltage, you can emit a specified frequency of sound, the frequency is determined by the internal oscillation circuit, Can not change.

Passive excitation resonant cavity open circuit buzzer The square wave signal provided by the circuit drives the vibration plate to vibrate. The air compression supplement time is relatively short, the vibration reduction is small, the vibration amplitude of the vibration plate is relatively large, suitable for low power consumption specifications or low frequency range response sound, and the tone is general;

On the contrary, the passive buzzer is suitable for higher current consumption specifications or Higher frequency range, and has a better tone.

If you want to know more about the difference of source buzzers, you can contact us. We are the manufacturer of source buzzers, and there are many professionals. We have a clear understanding of the difference between them. We can introduce the relevant knowledge of the source buzzer in detail to help you choose the right source buzzer.