How does a piezoelectric transducer convert electricity into vibration?

A piezoelectric transducer converts electricity into vibration through the converse piezoelectric effect.12

When an electric field is applied to a piezoelectric material—such as quartz or specific piezoelectric ceramics—it causes a physical distortion or strain in the crystal lattice. This occurs because the applied field induces small displacements of ions within the material's structure.132

To generate effective ultrasound, an alternating electric field is typically applied at the same frequency as the material's natural mechanical resonance. This synchronization significantly enhances the resulting mechanical vibration, allowing the transducer to produce high-frequency sound waves. By selecting specific shapes for the crystal, such as a concave surface, the resulting vibrations can be focused to meet the needs of various applications, including medical imaging and industrial cleaning.12