Piezoelectricity

About Piezoelectricity

• The term “piezoelectric” originates from the Greek words “piezein,” meaning ‘to squeeze’, and “elektron”, for amber – a material known for its association with static electricity.
• Piezoelectricity is a remarkable phenomenon whereby some materials – including quartz, ceramics such as lead zirconate titanate (PZT), and even certain biological substances like bone and the tendons – can generate an electric charge in response to mechanical stress.
• This property is the result of their unusual crystal structures.
• Usually, the charges on atoms in the molecules that make them up are symmetric on two sides of an axis.
• When some stress is applied, the molecule becomes distorted and the asymmetry of charges gives rise to a small electric current.
• Some materials also display an inverse piezoelectric effect, where the application of an electric current induces a mechanical deformation.
• Applications
  • Both direct and inverse piezoelectric materials are widely used in pressure sensors, accelerometers, and acoustic devices – where their ability to convert mechanical signals into electrical signals is crucial.
  • It is also used in quartz watches.
  • Piezoelectric transducers are common in ultrasonic applications, such as intrusion detectors and alarms. 
  • Piezoelectric devices are employed at AF (audio frequencies) as pickups, microphones, earphones, beepers, and buzzers. 
  • In wireless applications, piezoelectricity makes it possible to use crystals and ceramics as oscillators that generate predictable and stable signals at RF (radio frequencies).

Q1) What is Quartz?

It is a widely distributed mineral of many varieties that consists primarily of silica, or silicon dioxide. It is a crystal that develops positive and negative charges on alternate prism edges when it is subjected to pressure or tension. The charges are proportional to the change in pressure. 

Source: Piezoelectricity: Why quartz ticks