Piezoelectricity piezoelectric effect

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Piezoelectricity :

The crystals in which the dipoles align themselves in the same direction leading to resultant dipoles when certain external mechanical stress or pressure is applied on it are called piezoelectric and this phenomenon is called piezoelectricity. When some pressure (stress) is applied on such crystals there is displacement of ions in the crystal which result in the formation of electric current.
Therefore, such crystals are used as mechanical electrical transducers. For example, such crystals are used as pickups in record players as they produce electric signals when pressure is applied on them. Piezoelectric crystals are also used in microphones, ultrasonic generation, sonar detectors etc. 
      The reverse effect may also produce in these crystal when placed in an external electric field leading to the deformation .

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