What are the main structural principles of using buzzer? Buzzer is an electronic buzzer with integrated structure, which is powered by DC voltage. It is widely used as a sound device in electronic products such as computers, printers, copiers, alarms, electronic toys, automotive electronic equipment, telephones, timers and so on. Buzzers are mainly divided into piezoelectric buzzers and electromagnetic buzzers. The buzzer is represented by the letter "H" or "ha" in the circuit (the old standard used "FM", "zzg", "LB", "JD", etc.).

1. Voltage buzzer piezoelectric buzzer is mainly composed of multivibrator, piezoelectric buzzer, impedance matcher, resonance box, shell, etc. Some piezoelectric buzzers are also equipped with light-emitting diodes on the shell.
Multivibrator consists of transistor or integrated circuit. When the power is turned on (1.5 ~ 15V DC working voltage), the multivibrator vibrates and outputs an audio signal of 100 ~ 500Hz. The impedance matcher pushes the piezoelectric buzzer to sound.
The piezoelectric buzzer is made of lead zirconate titanate or lead magnesium niobate piezoelectric ceramic materials. Silver electrodes are plated on both sides of the ceramic sheet. After polarization and aging treatment, they are bonded with brass sheet or stainless steel sheet.
2. Electromagnetic buzzer electromagnetic buzzer consists 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 to generate a magnetic field. The vibrating diaphragm vibrates and sounds periodically under the interaction of electromagnetic coil and magnet.