Piezo electric Property

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A presentation on Piezo Electric Property

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Piezo electric Property

  1. 1. Piezo electric property BY, K.M.Bharthe XI-B
  2. 2. INTRODUCTION Piezo electricity is defined as a change in electric polarisation with a change in applied stress.
  3. 3. INTRODUCTION The word piezo is Greek for "push“. Crystals which acquire a charge when compressed, twisted or distorted are said to be piezoelectric. This provides a convenient transducer effect between electrical and mechanical oscillations.
  4. 4. INTRODUCTION The converse of piezo electric effect is the change of strain or stress in a material due to an applied electric field.
  5. 5. discovery It was discovered in 1880 by Jaques and Pierre Curie during studies into the effect of pressure on the generation of electric charge by crystals (such as quartz)
  6. 6. internal mechanism • The effect is explained by the displacement of ions in crystals that have a nonsymmetrical unit cell • When the crystal is compressed, the ions in each unit cell are displaced, causing the electric polarization of the unit cell.
  7. 7. internal mechanism • Because of the regularity of crystalline structure, these effects accumulate, causing the appearance of an electric potential difference between certain faces of the crystal. • When an external electric field is applied to the crystal, the ions in each unit cell are displaced by electrostatic forces, resulting in the mechanical deformation of the whole crystal.
  8. 8. internal mechanism Pictorial demonstration
  9. 9. internal mechanism • In simple words, Piezoelectric materials are crystalline solids whose asymmetric structures create an electric dipole moment in the crystal lattice, which is sensitive to both elastic strain and applied electrical field. • When an electrical field is applied to a piezoelectric material, a stress is induced and the material changes shape (called the piezoelectric effect).
  10. 10. Examples of piezo electric materials Piezoelectric materials can be divided in 2 main groups: crystals and ceramics. Crystals Quartz SiO2 Gallium orthophosphate Ceramics Barium Titanate BaTiO3 Lead Zirconate Titanate PZT Polymers Polyvinylidene DiFluoride PVDF
  11. 11. Working of quartz crystals Quartz crystals have piezoelectric properties, meaning that they are capable of changing a mechanical force into electricity, or an electric current into a mechanical force. A slice, or wafer, of quartz crystal will generate an electric current when it is subjected to pressure.
  12. 12. Working of quartz crystals
  13. 13. Working of quartz crystals This property is used in quartz watches and clocks,which have an accuracy of one second in every 10 seconds. 9
  14. 14. Other examples  The reverse piezoelectric effect is utilised in printing equipment, both in the home and on industrial production lines.  Simple speakers,watch beepers, portable stereo systems, and in mobile phones and computers.  In ultrasonic transducers, used for medical ultrasound imaging  TV remote controls and echolocation devices used to help drivers park their car.  Piezoceramic filters are used in: Radios and televisions Watch bleepers Battery operated smoke detector alarms
  15. 15. Pros • Have a high Stiffness value and produce a high output with very little strain • Ideal for rugged use. • Excellent linearity over a wide amplitude • Ideal for continuous online condition monitoring smart systems. Cons •Can be used only for dynamic pressure sensing as in case of static sensing the signals will decay away •Operation over long cables may affect frequency response and introduce noise and distortion, the cables need to be protected.
  16. 16. Future applications • New applications and potential uses of piezoelectric components are being identified in a number of different fields. • Piezoelectric components’ durability and low cost mean that as research and development continues, the range of commercial applications will also continue to grow rapidly. • The market for piezoelectric components is expected to see double digit growth in the next five years. New devices such as piezoelectric generators will see the highest growth, estimated at 51.5% annually.
  17. 17. Thanks for watching

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