Application of magnetic buzzer

Electromagnetic buzzers are widely used as sounding devices in electronic products such as computers, printers, copiers, alarms, electronic toys, automotive electronic equipment, telephones, timers, etc.The computer industry (motherboard buzzer, chassis buzzer, computer buzzer), printer (control panel buzzer), copier, alarm industry (alarm buzzer, alarm buzzer), electronic toy (music buzzer), agriculture, automotive electronic equipment industry, telephone machine (environmental buzzer), timer, air conditioning, medical equipment and other electroacoustic industries, environmental monitoring.

Working principle of magnetic buzzer

The electromagnetic buzzer is composed of a coil and a metal diaphragm. After applying a suitable voltage to both ends of the coil, the current flowing through the coil will generate a magnetic field, which causes the metal diaphragm to deform. If a changing current is provided, the buzzer will emit a sound. Battery based buzzers can be divided into active and passive buzzers based on whether there is an internal vibration source. The active buzzer has an internal oscillation source, which only requires applying appropriate voltage to both ends of the coil; The passive buzzer does not have an internal vibration source, so it needs to be driven externally by a square wave. Changing the square wave frequency can change the sound.

What is the difference between magnetic buzzers and piezoelectric buzzers?

The main areas of electromagnetic and piezoelectric buzzers in terms of structure Not just coils and piezoelectric ceramics. Electromagnetic buzzer due to coil storage At the moment when the coil is turned on or off, there will be spikes, which will affect the sound quality effect Fruit; And the piezoelectric buzzer does not have a coil, so there will be no spikes either The impact of pulses. In addition, the sound decibel and voltage of the piezoelectric buzzer Proportional, and the voltage level is generally higher than that of electromagnetic buzzers.

How to choose the appropriate buzzer:

There are many types and specifications of buzzers. An appropriate buzzer can consist of several main parameters (voltage, current, drive mode, size, connection/fixation), as well as the desired sound pressure and frequency.

Working voltage: magnetic buzzers can operate between 1.5-24 V, while piezoelectric buzzers can operate between 3 V and 220V. However, in general, it is best for piezoelectric buzzers to operate at a voltage of 9 V or higher.

Current consumption: According to different voltages, magnetic buzzers can generate currents of tens to hundreds of milliamperes, while piezoelectric buzzers only require a few milliamperes.Drive mode: Select active buzzer or passive buzzer according to specific requirements.Size: The size of the buzzer will affect the volume and frequency. The size of electromagnetic buzzers is generally 7mm-25mm, while the size of piezoelectric buzzers is 12mm-50mm.Sound pressure: A distance of 10 centimeters is usually used as the testing standard for the buzzer. If the distance is doubled, the attenuation is about 6dB. On the contrary, if the distance is shortened by twice, it will increase by 6dB. The electromagnetic buzzer can reach a level of 85dB/10cm, while the piezoelectric buzzer can emit a louder sound. Most commonly used alarms use piezoelectric buzzers.

Selection of electromagnetic buzzer:

Drive method: If the frequency signal cannot be provided to the buzzer for operation, the drive circuit is included and a DC voltage can be applied.

Size: Size affects frequency, while smaller sizes have higher frequencies.

Voltage size: calculated in V O-P (1/2 square wave).

Fixed method: DIP is the cheapest, followed by soldering wire, and SMD has the highest cost.

Welding method: Hand welding, with a lower frequency of air holes at the bottom, passing

through the furnace. Selection:

Drive method: If the frequency signal cannot be provided to the buzzer for operation, the drive circuit is included and a DC voltage can be applied.

To choose an electromagnetic buzzer, you need to first know what type of electromagnetic buzzer you need, and then based on your actual knowledge of the size, voltage, and driving mode of the selected electromagnetic buzzer, you can make the selection.

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