What are the working principles of electromagnetic buzzer


The alternating current signal of the electromagnetic buzzer generates alternating magnetic flux on the rod of the bracket through the wire wound on the bracket. The alternating magnetic flux overlaps with the constant magnetic flux of the magnet ring, so that the molybdenum sheet vibrates at the specified frequency of the alternating current signal and produces sound together with the resonator. Then, let's learn about the working principles of the electromagnetic buzzer!


What is the structure of the electromagnetic buzzer?

The overall frequency and sound pressure response curve of the speaker product are directly related to the gap value, the natural frequency of the molybdenum plate (which can be roughly refracted to the thickness of the small molybdenum plate), and the frequency of the shell), and the Helmholtz resonator. After the buzzer chip, the specific oscillation circuit and the resonator are combined, it will become the completed buzzer. What you remove from the induction cooker is only a honeycomb, there is no oscillating circuit, and the resonator is in the shell of the induction cooker! Making a buzzer requires a resonator and an oscillating circuit. Resonators also need to know. If there is no resonator, the sound will be smaller! In addition, each beehive has an inherent vibration frequency, and only at this frequency can it make a stronger sound.

If only there were means of testing. The frequency of action of the buzzer on the hand can be measured. Then, an oscillation circuit of this frequency is manufactured, and a resonator is manufactured. Here is the oscillation circuit. The oscillation frequency needs to be adjusted according to the frequency of the buzzer.

can generally use a low-power buzzer. To make an alarm sound, a modulation circuit must be installed on the oscillation circuit to make the same sound as an alarm clock. Like the previous circuit, the oscillation frequency is more than 100 times smaller. The electromagnetic buzzer uses a piezoelectric material. That is, when the piezoelectric material is deformed by an external force, the piezoelectric material generates an electric charge. Similarly, piezoelectric materials deform when energized. The electromagnetic buzzer mainly uses the characteristic that the energized conductor can generate a magnetic field, and presses the eardrum fixed on the coil by the magnetic force generated by the fixed magnet and the energized conductor.

The electromagnetic buzzer is composed of a coil and a metal diaphragm. After an appropriate voltage is applied to both ends of the coil, if a current flows through the coil, a magnetic field will be generated, and the metal diaphragm will be deformed by the magnetic field. The buzzer will sound when a varying current is supplied. The electromagnetic buzzer can be divided into active buzzer and passive buzzer according to whether there is an oscillation source inside. There is an oscillation source inside the active buzzer, as long as the appropriate voltage is applied to both ends of the coil; there is no oscillation source inside the passive buzzer, so it needs to be driven by a square wave outside. Changing the frequency of the square wave changes the sound.

Due to the different pronunciation principles of the two buzzers, the piezoelectric structure is simple and durable, but due to the single tone and poor timbre, it is suitable for equipment such as sirens. Electromagnetic sound is very good, used for sound, music and other equipment.

What is introduced above is the working principle of the electromagnetic buzzer. If you need to know more, please feel free to contact us!

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