Buzzer is an electronic structure with integrated structure. It is powered by DC voltage and is widely used as a sounding device in computers, printers, copiers, alarms, electronic toys, automotive electronics, telephones, timers and other electronic products. . The buzzer is mainly divided into two types: a piezoelectric buzzer and an electromagnetic buzzer. The buzzer is represented by the letter "H" or "HA" in the circuit (old standards used "FM", "ZZG", "LB", "JD", etc.).

The sounding principle of the buzzer is composed of a vibration device and a resonance device, and the buzzer is divided into a passive and excited type.

The working sounding principle of the passive separately excited buzzer is: the square wave signal input resonance device is converted into a sound signal output. The working sounding principle of the passive separately excited buzzer is as follows:

The working sound principle based on the excitation buzzer is as follows: The direct current power input passes through the amplification sampling circuit of the oscillation system to generate a sound signal under the action of the resonance device. The working sound principle derived from the excitation buzzer is as follows:

The main differences between active buzzers and passive buzzers are:

1. The fundamental difference between an active buzzer and a passive buzzer is that the product requires different input signals.

2. The ideal signal for the active buzzer to work is direct current, which is usually marked as VDC, VDD, etc. Because there is a simple oscillation circuit inside the buzzer, it can convert a constant DC power into a pulse signal of a certain frequency, and the magnetic field alternates from the surface to drive the molybdenum plate to vibrate and sound.

3. However, some active buzzers can also work under certain AC signals, but the voltage and frequency of AC signals are very high. This mode of operation is generally not used.

4. The passive buzzer does not have an internal driving circuit. Some companies and factories call it a siren, and the national standard is called a siren. Ideal signal square wave for passive buzzer operation. If the pre-DC signal buzzer is not responding, because the magnetic circuit is constant, the molybdenum sheet cannot vibrate.