Piezoelectricity is the phenomenon where certain materials generate an electric charge when subjected to mechanical stress—such as squeezing, bending, or stretching. This effect is reversible, meaning that applying an electric field to the material can also cause it to change shape or deform slightly.
Piezoelectricity occurs in materials with non-centrosymmetric crystal structures, where the internal arrangement of positive and negative charges becomes unbalanced under stress. This creates an electric potential across the material.
Common piezoelectric materials include:
- Quartz crystals,
- Rochelle salt,
- Ceramics like lead zirconate titanate (PZT),
- Biological materials like bone and DNA.
Piezoelectricity has many practical applications:
- Sensors and accelerometers (convert pressure into electrical signals),
- Microphones and speakers (convert sound vibrations to signals and vice versa),
- Lighters and ultrasound devices (generate sparks or high-frequency sound waves),
- Energy harvesting (converting vibrations or motion into electricity).
Piezoelectric materials bridge the mechanical and electrical worlds, making them essential for both everyday devices and advanced precision technologies.