Explanation

When some dielectric single crystal are subjected to directional pressure, they can make the surfaces of crystal perpendicular to the stress have the same amount of opposite charges. The charge density is proportional to the stress, which is called positive piezo electricity; If the direction of stress is reversed, the charges on the surfaces on both sides change sign. On the contrary, if an exciting electric field is applied, the medium will produce mechanical deformation; The strain is proportional to the electric field strength, which is called the inverse piezoelectric effect. Ferroelectric ceramics, such as BaTi03, PbTi03, etc., all have polarization treatment. Various piezoelectric devices can be made by using the characteristics of materials. They have important applications in energy conversion, filtering, frequency stabilization, high-voltage generation, signal processing, ultrasonic emission and other fields.

Classification