how does piezoelectric diaphragm buzzer works ?

The sound source of the electric piezo diaphragm buzzer sound element is mainly from the piezoelectric ceramic sheet. The piezoelectric ceramic piece is composed of a piezoelectric ceramic plate printed with electrodes on both sides and a metal plate (brass or stainless steel, etc.). The adhesive is used to bond the piezoelectric vibrating plate to the metal sheet. This is what we call a piezo diaphragm buzzer.

The operation principle of the piezo buzzer element piece is that when a direct current voltage is applied between the two electrodes of the piezoelectric vibration plate, mechanical deformation is caused due to the piezoelectric effect. For a piezo ceramic bimorph is having a shape distortion, its deformation is extended in the radiation direction. Therefore, when the alternating voltage is passed through the electrode, the bending alternately occurs repeatedly, thereby generating sound waves in the air and making a sound.