Active buzzer

The active buzzer is an electronic sounder with an integrated structure. It is powered by DC voltage and is widely used in electronic products such as computers, printers, copiers, alarms, electronic toys, automotive electronic equipment, telephones, and timers. Sound device. Buzzers are mainly divided into two types: piezoelectric buzzers and electromagnetic buzzers. The buzzer is represented by the letter "H" or "HA" in the circuit (the old standard uses "FM", "LB", "JD", etc.).

active buzzer

How Active Buzzers Work

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

Multivibrators are built from transistors or integrated circuits. When the power is turned on (1.5~15V DC working voltage), the multivibrator starts to oscillate and outputs an audio signal of 100~500Hz, and the impedance matching device pushes 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 bonded together with brass or stainless steel sheets.


2. Electromagnetic buzzer 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 is wound between the electromagnetic coil and the magnet

buzzer

(1) Preparation of electromagnet M: Wind 100 turns of wire on an iron bolt with a length of about 6 cm, leave 5 cm at the end of the wire as a lead wire, stick the coil with transparent tape to prevent the coil from loosening, and then stick it with tape On a box, the electromagnet is ready.

(2) Preparation of shrapnel P: Cut a long iron sheet with a width of about 2 cm from the tin can, bend it into a right angle, connect a lead wire of the electromagnet to the shrapnel, and stick the shrapnel to the wooden board with adhesive tape.

(3) Use a paper clip as the contact Q, use a book to raise the paper clip, stick it firmly with adhesive tape, lead out a wire, and connect the circuit.

(4) Adjust the distance between M and P (by moving the box), so that the electromagnet can attract the shrapnel, adjust the distance between the contact and the shrapnel, so that they can just touch, and you can hear the buzzing sound after power on.


Features of Active Buzzer

1. The inside of the active buzzer is equipped with a shock source, so it will buzz as soon as it is powered on.

2. Its program control is also very convenient. Setting a high or low level to the single chip microcomputer can make it sound, but the passive buzzer can't do it.

3. Function of active buzzer
The active buzzer has an additional vibration source than the passive buzzer in terms of structure. The addition of this part makes it sound as long as it is powered on during use. This feature is used in various machines In , the main function is to remind the operation, which can be an end reminder or a fault reminder.

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