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The structure principle of the buzzer

1. Piezoelectric buzzer

The piezoelectric buzzer is mainly composed of a multivibrator, a piezoelectric buzzer, an impedance matcher, a resonance box, and a shell. Some piezoelectric buzzers are also equipped with light-emitting diodes.

The multivibrator is composed of transistors or integrated circuits. When the power is turned on (1.5~15V DC working voltage), the multivibrator starts to vibrate and outputs 1.5~2.5kHZ audio signals, and the impedance matcher drives the piezoelectric buzzer to sound.

The piezoelectric buzzer is made of lead zirconate titanate or lead magnesium niobate piezoelectric ceramic material. Silver electrodes are plated on both sides of the ceramic sheet, and after polarization and aging treatment, they are then glued together with the brass sheet or the stainless steel sheet.

2. Electromagnetic buzzer

The electromagnetic buzzer is composed of oscillator, electromagnetic coil, magnet, vibrating diaphragm and shell. After the power is turned on, the audio signal current generated by the oscillator passes through the electromagnetic coil, causing the electromagnetic coil to generate a magnetic field. The vibrating diaphragm periodically vibrates and produces sound under the interaction of the electromagnetic coil and the magnet.