Buzzer manufacturer introduces the principle of buzzer sheet composition and identification of positive and negative orientations:

The buzzer disc, also known as a piezoelectric ceramic buzzer disc, is one of the application products in piezoelectric ceramics.

Piezoelectric buzzers primarily consist of a buzzer disc. These discs are made from piezoelectric ceramic materials such as lead zirconate titanate or lead magnesium niobate. Silver electrodes are deposited on both sides of the ceramic disc, which is then polarized and aged before being bonded with brass or stainless steel sheets.

Piezoelectric buzzers operate on the principle of the piezoelectric effect; when subjected to alternating voltage, they generate mechanical vibrations. Conversely, when mechanical force is applied to them, they also produce voltage signals. Therefore, piezoelectric ceramic buzzers can be conveniently used as vibration sensors.

Piezoelectric ceramic buzzers generate a very weak voltage signal when subjected to mechanical force, and as vibration sensors, they typically require connection to a voltage amplifier. How can the orientation of the positive and negative charges in the buzzer be identified?

The polarity for sound-emitting buzzers is typically not separated. However, for inductive buzzers, it's essential to differentiate the positive and negative poles.

Typically, the positive pole is facing upwards. Use a multimeter with a pointer and set it to the 25V range. Gently pinch both sides of the buzzer with your left thumb and index finger, while holding the two test leads in your right hand. Bring the red lead close to the silver surface of the buzzer and place the black lead horizontally on the metal surface of the buzzer. Then, firmly press down with your left thumb and index finger, and release. This will generate two voltage signals with opposite polarities on the buzzer, causing the pointer to swing right, then back to zero, then left, and back to zero, with an amplitude of approximately 0.1 to 0.15V. In this situation, the buzzer is oriented with the positive pole upwards.

If the pointer swings in the order of left - reset - right - reset, the buzzer diaphragm is facing downwards. Under the same pressure, the greater the pointer's swing amplitude, the higher the sensitivity of the buzzer diaphragm.