Quality identification of buzzer

The piezo diaphragm film, also called piezoelectric ceramic buzzer,which is one of the most widely used products in piezo alarm element. The piezo diaphragm buzzer is the main component of the piezo disc benders.

 

The piezoelectric buzzer is made of lead zirconate titanate or lead magnesium niobate piezoelectric ceramic material. Silver electrodes are plated on both sides of the piezo ceramic crystal, and after polarization and aging treatment, they are adhered to the brass sheet or the stainless steel sheet.

 

The piezo disc benders ceramic works on the principle of piezoelectric effect, which generates mechanical vibration when an alternating voltage is applied thereto; on the contrary, it also generates a voltage signal when a mechanical foe is applied thereto. Therefore, the piezoelectric ceramic buzzer can be used as a vibration sensor. When the piezoelectric ceramic buzzer is subjected to mechanical force, the voltage signal generated is very weak. Generally, the voltage sensor should be connected to the voltage amplifier.

 

The method of using a mechanical multimeter to detect the quality of a piezoelectric ceramic buzzer : Turn the multimeter to 2. 5V, and gently press the left thumb and index finger on both sides of the buzzer. Holding two test leads on the right, the red pen is connected to the metal piece, and the black pen is placed on the surface of the piezo buzzer. Then the left thumb and the index finger are pressed slightly, and then relaxed. The buzzer produces two voltage signals of opposite polarity, so that the pointer swings to the right → returns to zero → swings to the left → returns to zero, and the swing is about 0. 1~0. 15V.

 

If you exchange the test pen position and re-experiment, the order of the pointer swing is: swing to the left → return to zero → swing to the right → return to zero. Under the same pressure, the larger the pointer swing, the higher the sensitivity of the PZT piezo bimorph. If the pointer does not move, it indicates that the piezo buzzer is leaking or damaged inside. The capacitance of the piezo buzzer can be directly measured by the digital capacitance , and its capacitance should be in the range of 0.005~0. 02∧F.