How Do Piezoelectric Crystals Work?


Quick Answer

The asymmetric shape of the atoms of piezoelectric crystals creates positive and negative poles sensitive to electricity and deformation. This causes the crystal to produce a small voltage when it is vibrated or when enough pressure is applied to change the shape of the crystal. This effect is reversible; when an electric voltage is applied, the crystal changes shape by a small amount.

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Full Answer

One of the best known uses of piezoelectric crystals is in a cigarette or a gas grill lighter, where pressing the button causes a spring-loaded hammer to strike the crystal. This pressure deforms the crystal and creates a high voltage that ignites the gas as the current jumps a small spark gap.

The auto focus in a digital camera also uses piezoelectric crystals, notes Green Energy Help Files. Vibrations applied at a certain frequency to two surfaces of the crystal create a force between them. One surface is fixed, and the other surface is forced to move.

Piezoelectric crystals are used in buzzers by oscillating a current through the crystal, causing it to vibrate, according to Wikipedia. The crystals are also useful in some types of actuators for aerospace applications. A voltage is applied to cause a linear deformation. Although the deformation is small, these actuators generate a large amount of force.

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