Structure and Principle of Piezoelectric Buzzer
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Keywords : 带式干燥机应用范围,带式干燥机选型
Piezo buzzer mainly composed of multivibrator, piezoelectric buzzer, impedance matching and resonance box, shell and other components. Some piezoelectric buzzer shell is also equipped with light-emitting diodes. The multivibrator consists of a transistor or an integrated circuit. When the AC voltage is added, it will cause mechanical deformation and contraction due to the piezoelectric effect, and this feature causes the metal piece to vibrate and sound.
To distinguish the way to do the distinction between the piezoelectric buzzer is roughly divided into the feedback buzzer (self-excited) and no feedback buzzer (external) two. When the feedback buzzer with positive feedback oscillator circuit will produce a resonant cavity with the same frequency of the single tone; and no feedback buzzer can be used with external oscillation circuit, select any frequency sound.
The following are two kinds of piezoelectric buzzer fixed way: a. Peripheral support - the buzzer outer diameter edge fixed in the resonant cavity, generally without feedback buzzer, and its buzzer must be with the resonance Cavity frequency with, will have a higher sound pressure output, and by the external oscillation circuit to generate a signal to make the buzzer sound. B. Node support - Fix the buzzer in an annular structure of the same size as the ceramic plate diameter. If the resonator design is appropriate, and with the correct frequency of the feedback buzzer and positive feedback circuit, will have a greater sound pressure and the correct frequency.