Piezoelectric ceramic buzzer is a kind of device used in piezoelectric ceramic. Titanium and piezoelectric ceramic sheets (PZT) prepared by zirconium and lead oxides and sintered are commonly used. In order to improve the low-frequency response, double diaphragm structure is generally used.
(1) Basic principle
(2) Application
(3) Test method
(4) Product features
(1) Basic principle
In ionic crystals, positive and negative ions are regularly staggered to form a crystal lattice. In this way, the intrinsic electric moment is formed, and polarized charges appear on the surface of the crystal. Since the crystal is exposed to the air, after a period of time, these charges are neutralized by the different number ions falling on the crystal surface and in the air. Therefore, the polarized surface charges and electric moments will not appear. However, when the crystal is mechanically deformed, the lattice will change. In this way, the electric moment changes, and the surface polarization charge value also changes. Thus, the positive or negative charge on the surface has a measurable increment (increase or decrease), which is the amount of electricity of the piezoelectric effect.
(2) Application
Piezoelectric ceramic buzzer is widely used in electronic clocks, car horns, audio, communications, remote sensing, calculators, electronic toys and other products.
(3) Test method
The method to test the quality of piezoelectric ceramic buzzer with a mechanical multimeter is: turn the multimeter to 2.5V, and gently pinch both sides of the buzzer with the left thumb and index finger. The right hand holds two probes, the red probe is connected to the metal sheet, and the black probe is placed horizontally on the surface of the buzzer sheet. Then the thumb and index finger of the left hand are slightly pressed, and then relaxed. Two voltage signals of opposite polarity are generated on the buzzer, causing the pointer to swing to the right → return to zero → swing to the left → return to zero, with a swing of about 0.1 ~ 0.15v.
If the test is repeated after the position of the stylus is changed, the order of the pointer swinging is: swing left → return to zero → swing right → return to zero. Under the same pressure, the greater the swing of the pointer, the higher the sensitivity of the buzzer. If the pointer does not move, it indicates that the buzzer has internal leakage or damage. The capacitance of the buzzer can be directly measured with a digital capacitance meter, and the capacitance should be within the range of 0.005 ~ 0.02 Λ F.
(4) Product features
/- High sensitivity and low energy consumption
/- Good reliability and stability
/- High and low temperature resistance and long service life
/- Thin thickness and light weight
/- Small size, high pressure resistance
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