Electromagnetic buzzer is a kind of buzzer, which is different from piezoelectric buzzer. Electromagnetic buzzer is an electronic buzzer that uses the action of electromagnetic coil on the buzzer to sound. As a sounding device.

　　1, passive
　　 The resonant cavity sealed buzzer is the opposite after it is excited, which is suitable for higher current consumption specifications/higher frequency range response sound, and the sound quality is better; (40~80mA*500Hz).

　　2, active
　　 Active (self-excited) buzzer vibration coil and oscillating coil are combined into one.

Buzzers are divided into two categories: piezoelectric and electromagnetic: piezoelectric buzzer uses the piezoelectric effect of piezoelectric ceramics to drive the vibration of the metal sheet to produce sound; electromagnetic buzzer uses The principle of electromagnetism, the metal vibrating membrane is sucked down when it is energized, and it bounces back according to the elastic force of the vibrating membrane when it is not energized, so the piezoelectric buzzer is driven by square wave, electromagnetic is driven by 1/2 square wave, piezoelectric A type buzzer requires a relatively high voltage to have sufficient sound pressure, and it is generally recommended to be above 9V. Some piezoelectric specifications can reach more than 120dB, and larger sizes can easily reach 100dB.

Electromagnetic buzzer: With 1.5V, it can emit a sound pressure of more than 85dB, but the current consumption will be much higher than that of piezoelectric buzzer. In the same size, the electromagnetic buzzer has a response frequency It can be done relatively low; the sound pressure of electromagnetic buzzer is generally up to 90dB. Mechanical buzzer is a small category of electromagnetic buzzer.