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Applications of piezo-electricity

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Applications of piezo-electricity

  1. 1. By- Sakti Prasanna 1
  2. 2. OVERVIEW 1) Introduction 2) Cause of piezoelectricity 3) Discovery 4) Materials exhibiting this property 5) Field of applications 6) Mechanism of some applications 7) Conclusion 2
  3. 3. WHAT THE PIEZOELECTRICITY IS Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. 3
  4. 4. Reverse piezoelectric effect: when voltage is applied on two opposite surfaces of a piezoelectric material that shows expansion or contraction.  Piezoelectricity is derived from the Greek word “piezo” or “piezein” which means to squeeze or press. 4
  5. 5. CAUSE OF PIEZOELECTRICITY Piezoelectric effect is formed in crystal having no centre of symmetry. 5
  6. 6. DISCOVERY Piezoelectric effect was first proven in 1880 by the French Physicist brothers Pierre and Jacques Curie Pierre Curie Jacques Curie 6
  7. 7. MATERIALS EXHIBITING THE PROPERTY: NATURAL OCCURING MATERIALS: 1) Quartz(SiO2) 2) Sucrose (table sugar) 3) Rochelle salt 4) Topaz(Al2SiO4(F,OH)2) 5) Dry bone 6) Dentine SYNTHETIC MATERIALS: 1) Barium titanate (BaTiO3) 2) Lead zirconate titanate 3) Potassium niobate (KNbO3) 4) Bismuth ferrite (BiFeO3) 5) Sodium niobate (NaNbO3) 7
  8. 8. APPLICATION FIELDS A. As high voltage power source:  LPG stove Lighter and Cigarette lighter  Energy harvesting in micro scale (New concept)  Piezoelectric transformer (New concept) B. Sensors and Actuators:  High precision piezoelectric microphones  Electric guitar pickup  Piezoelectric micro balance (very sensitive chemical and biological sensors)  Strain gauge  Electronic drum pad  Pressure sensors  Accelerometer (New concept)  Loud speaker and buzzer(Actuator) 8
  9. 9. C. As frequency standard:  General quartz clock  Crystal oscillator D. Sonic and Ultra sonic applications  Underwater submarine detection  Ultrasound in medical technology  Metal fault detection 9
  10. 10. E. Piezoelectric motor:  A piezoelectric motor or piezo motor is a type of electric motor based upon the change in shape of a piezoelectric material when an electric field is applied.  Piezoelectric motors make use of the converse piezoelectric effect whereby the material produces acoustic or ultrasonic vibrations in order to produce a linear or rotary motion due to friction. 10
  11. 11. Mechanism of piezo-motor: 11
  12. 12. Uses of piezoelectric motor:  Movement of camera lens  Rotation of radar  Very small scale valve control  Laser movement in case of biomedical modern operations Advantages:  No stray field effect  High resolution and high accuracy  Rapid response  Wide range of angular steps and angular velocities Disadvantages:  Necessity for a high frequency power supply  Large scale devices are impossible 12
  13. 13. MECHANISM OF LPG STOVE LIGHTER When a piezoelectric material is hammered a high voltage is generated and causes spark. Which is the basis of piezoelectric LPG lighter. 13
  14. 14. Piezoelectric Igniter 14 Lead zirconate titanate (PZT)
  15. 15. Cigarette Lighters: 15
  17. 17. Clock uses piezoelectric quartz crystal Oscillator as frequency standard for tracking the time.  Battery provides current to input microchip circuit  Input microchip circuit makes quartz crystal (precisely cut and shaped like a tuning fork) oscillate (vibrate) 32768 times per second.  Output microchip circuit detects the crystal's oscillations and turns them into regular electric pulses, one per second.  Electric pulses drive miniature electric stepping motor. This converts electrical energy into mechanical power.  Electric stepping motor turns gears.  Gears sweep hands around the clock-face to keep time 17
  18. 18. Crystal Oscillators: 18 Crystal oscillators are not only used in clock but in all microprocessor based digital systems
  20. 20.  An ac voltage is applied to the VIN electrodes, causing mechanical expansion and compression in the thickness direction.  This displacement on the primary is transferred as a force in the longitudinal or length direction.  Mechanical resonance occurs Due to transverse and longitudinal vibration.  Voltage gain is a function of the PZT is given by 20 Where g(w) is piezoelectric material co- efficient
  22. 22. ENERGY HARVESTING USING PIEZOELECTRICITY Vibrations can be used to generate electricity in micro scale using piezoelectric materials. Sources of vibration:  Walk sides  Railway tracks  Shoes or boots  Mobile keypad and keyboard  Floor mat, tiles and carpets 22
  23. 23. 23 This is the circuit for utilisation of generated energy. The generated ac voltage is rectified and stored in a capacitor for use. Also trickle charge can be provided to a battery to recharge it.
  24. 24. CONCLUSION  Revolutionary concept in the field of sensors and transducers.  There are also some future aspects those need to be developed such as piezoelectric accelerometer, motor, underwater acoustic transducers, piezoelectric transformers ect.  Energy harvesting through piezoelectricity is both economical and eco-friendly. 24
  25. 25. REFERENCES BOOKS  J.P. Bentley, Principles of Measurement Systems- Pearson Education  William D. Callister, David G. Rethwisch, Material Science and Engineering an introduction, Wiley Publication  How it works, The clock, A CBT Publication  K. Krishna Murty, How things work?, Pustak Mahal WEB       25
  26. 26. 26