The working principle and difference of electromagnetic buzzer and piezoelectric buzzer

buzzer is a commonly used sound element in the design of electronic products. According to the different working principles, it can be divided into electromagnetic buzzer and piezoelectric buzzer. Electromagnetic buzzer is often used in development board and experimental board. The principle of

electromagnetic buzzer

electromagnetic buzzer is composed of a coil and a metal diaphragm. After a suitable voltage is applied to both ends, the current flowing through the coil will generate a magnetic field. The magnetic field causes the metal diaphragm to deform. If a varying current is supplied, the buzzer will sound. The battery buzzer can be divided into active buzzer and passive buzzer according to whether there is an internal oscillation source. The active buzzer has an oscillation source inside, and only needs to add a suitable voltage at both ends; while the passive buzzer has no oscillation source inside, so it needs to be driven by a square wave outside, and the frequency of the square wave can be changed. sound.

piezoelectric buzzer is based on the piezoelectric effect of piezoelectric ceramics to drive the vibration of metal sheets to produce sound. Using the principle of electromagnetism, the metal diaphragm is sucked down after being energized, and the elastic force of the diaphragm bounces back when not energized.

And after the electromagnetic buzzer is turned on, the audio signal current generated by the oscillator will pass through the electromagnetic coil, causing the electromagnetic to generate a magnetic field, then the vibrating diaphragm will be under the interaction of the electromagnetic and the magnet, Vibrated periodically.

electric buzzer principle

electric buzzer by piezoelectric effect, mainly by the piezoelectric ceramic and metal diaphragm. When the piezoelectric ceramic is energized, the piezoelectric ceramic will change, driving the metal diaphragm to deform, and the metal diaphragm will restore the original deformation after the voltage is removed. Therefore, sound can only be generated by applying a varying voltage to the piezoelectric ceramic. The ultrasonic device is also realized by this.

And the electromagnetic buzzer is mainly composed of the following parts: oscillator, electromagnetic coil, magnet, vibrating diaphragm, housing.

the difference between the two

electromagnetic buzzer piezoelectric buzzer in the structure of the main difference is the coil and piezoelectric ceramic. Because of the existence of the coil, the electromagnetic buzzer will produce a peak when it is on and off, which will affect the sound quality. But the piezoelectric buzzer has no wires, so there will be no spikes. In addition, the sound of the piezoelectric buzzer is proportional to the voltage, generally higher than the electromagnetic buzzer.

The driving mode of both

The two buzzers are basically similar, and both can use triodes. For passive buzzers, a freewheeling diode is required, while active buzzers and piezoelectric buzzers are not required.

The above is the difference between the principles of piezoelectric buzzer and electromagnetic buzzer. No matter which one, it has its own characteristics and advantages. The editor reminds you that you can choose according to your needs.