What is piezoelectric buzzer? Where is it mainly used?

The piezoelectric buzzer is an electromagnetic device that emits a buzzer-like sound. Commonly used to replace electric bells or as audio current generators. Piezoelectric buzzer is an electronic buzzer with integrated structure, powered by DC voltage. It is widely used in household appliances, banks, computers, printers, photocopiers, electronic toys, automotive electronic equipment, telephones, timers, Police alarm systems and other electronic products.

1. piezoelectric buzzer driving principle

Compared with led , the buzzer requires more current, and some buzzers require more current than the UNO port of the Arduino can provide More current. Therefore, the drive buzzer is not just connected to the port like the drive LED , but is implemented by using a triode. When port 2 outputs high level 5V , transistor Q1 is turned on, which is equivalent to switch on. When port 2 outputs a low level of 0V , transistor Q1 is turned off, which is equivalent to switch off.

Classification of 2. piezoelectric buzzers

Buzzers are mainly divided into piezoelectric buzzers and electromagnetic buzzers. The buzzer uses the letter "H " or "HA " to indicate ( The old standard used "FM ", "ZZG ", "LB ", "JD ", etc. ) .

1. Piezoelectric Buzzer

Piezoelectric Buzzer is mainly composed of multivibrator, piezoelectric buzzer, impedance matching device, resonant box, shell, etc. Some piezoelectric buzzer housings are also equipped with light-emitting diodes.

Multivibrator consists of transistors or integrated circuits. When the power supply is turned on (1.5~15V DC working voltage ) , the multivibrator starts to vibrate, and the audio signal of 1.5~2.5kHz is output, and the impedance matching device drives the piezoelectric buzzer to sound.

The piezoelectric buzzer is made of lead zirconate titanate or lead niobate piezoelectric ceramic materials. The ceramic plate is plated with silver electrodes on both sides, and after polarization and aging treatment, it is bonded with brass plate or stainless steel plate.

2. Electromagnetic Buzzer

Electromagnetic Buzzer is composed of oscillator, electromagnetic coil, magnet, diaphragm and housing. 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 diaphragm periodically vibrates and sounds under the interaction of the electromagnetic coil and the magnet.

3. piezoelectric buzzer function

piezoelectric buzzer is also widely used in our daily life.

The buzzer used in the washing machine often beeps to prompt the user to operate the process.

The beeper used in the combustion equipment is mainly used to issue an alarm to warn the user that the combustion equipment is dry burning.

The buzzer used as a doorbell often emits a "ding-dong" sound or musical sound to indicate a guest visiting.

Buzzers installed in police, bank and home warning areas often sound the alarm. If someone enters the warning area, under the control of induction, the buzzer will sound an alarm.

Piezoelectric buzzers used in factories, schools, etc., often ring.