Piezoelectricity & Its Applications


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In an age where every teeny tiny bit of electricity is valued, conservation is much talked about, can piezoelectricity be the messiah to ease the burden off the conventional energy sources?
Who says it cannot?
Presentation as a part of seminar coursework.

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Piezoelectricity & Its Applications

  1. 1. By: AZEEM AHMAD KHAN ELECTRONICS ENGG. A4LE 44 Under the Guidance of : Prof. MJR Khan Sb.
  2. 2. INTRODUCTION  Piezoelectricity was discovered by Curie brothers in 1880.  It is the generation of electric field from applied pressure.  It is observed in crystalline materials with no inversion symmetry.  The materials exhibiting the direct piezoelectric also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field).
  3. 3. MATERIALS NATURAL SYNTHETIC Quartz Lead zirconate titanate (PZT) Rochelle Salt Zinc oxide (ZnO) Topaz Barium titanate (BaTiO3) Sucrose Gallium orthophosphate (GaPO4) Tendon Potassium niobate (KNbO3) Silk Lead titanate (PbTiO3) Enamel Lithium tantalate (LiTaO3) Dentin Langasite (La3Ga5SiO14) DNA Sodium tungstate (Na2WO3)
  4. 4. WORKING  The positive & negative charges are symmetrically distributed in a crystal.  Piezoelectric ceramic materials are not piezoelectric until the random ferroelectric domains are aligned by a process known as POLING.  Poling consists of inducing a DC voltage across the material.
  5. 5. Contd. Fig: (a) Random orientation of domains prior to poling (b) Poling in DC Electric Field (c) Remanent polarization after field is removed
  6. 6. Contd.  When pressure is applied to an object, a negative charge is produced on the expanded side and a positive charge on the compressed side.  Once the pressure is relieved, electrical current flows across the material.
  10. 10. GYMS AND WORKPLACES  Vibrations caused from machines in the gym.  At workplaces, piezoelectric crystal are laid in the chairs for storing energy.  Utilizing the vibrations in the vehicle like clutches, gears etc.
  11. 11. MOBILE KEYPADS & KEYBOARDS  Crystals laid down under keys of mobile unit and keyboard.  For every key pressed vibrations are created.  These vibrations can be used for charging purposes.
  12. 12. POWER GENERATING BOOTS OR SHOES  Idea was researched in US.  To power the battlefield equipment by generators embedded in soldier boots.  Idea was abandoned due to the discomfort.
  13. 13. FLOOR MATS AND PEOPLE POWERED DANCE CLUBS  Series of crystals can be laid below the floor mats, tiles and carpets.  One footstep can only provide enough electrical current to light two 60-watt bulbs for one second. [source: Christian Science Monitor].  When mob uses the dance floor, an enormous voltage is generated.  This energy is used to power the equipment of nightclubs.
  14. 14. OUTPUT POWER  The output voltage obtained from a single piezoelectric crystal is in millivolt(mV) range, which is different for different crystals.  And the wattage is in microwatt(µW) range.  In order to achieve higher voltages, the piezoelectric crystals can be arranged in series.  Used to charge batteries for backup supplies or to power low-power microprocessors.
  15. 15. OTHER APPLICATIONS:  Electric cigarette lighter: Pressing the button of the lighter causes a spring-loaded hammer to hit a piezoelectric crystal, producing a sufficiently high voltage that electric current flows across a small spark gap, thus heating and igniting the gas.  As sensing elements: Detection of pressure variations in the form of sound is the most common sensor application, e.g. piezoelectric microphones. Sound waves bend the piezoelectric material, creating a changing voltage.
  16. 16. ADVANTAGES Unaffected by external electromagnetic fields. DISADVANTAGES They cannot be used for truly static measurements Pollution Free Can pick up stray voltages in connecting wires. Low Maintenance Crystal is prone to crack if overstressed. Easy replacement of equipment. May get affected by long use at high temperatures.
  17. 17. CONCLUSION  Piezoelectricity is a revolutionary source for “GREEN ENERGY”.  Flexible piezoelectric materials are attractive for power harvesting applications because of their ability to withstand large amounts of strain.  Convert the ambient vibration energy surrounding them into electrical energy.  Electrical energy can then be used to power other devices or stored for later use.
  18. 18. REFERENCES:  “Piezoelectric Electric based energy harvesting” Nuthan      Raju, V. Karthik ,T.P Mohd Jaffar Ahmed Khan. Tomasz G. Zielinski, “ Fundamentals of piezoelectricity”, Institute Of Fundamental Technological Research, Warsaw, Poland. Tanvi Dikshit, Dhawal Shrivastava, (February 25,2010), “ Energy Harvesting via Piezoelectricity”. http://www.electroschematics.com/4301/piezoelectricitydesign-notes. (http://web.archive.org/web/20101006002651/http://www.e etimes.com/electronics-news/4197064/PiezoelectricTechnology-A-Primer) http://www.instrumentationtoday.com/piezoelectrictransducer/2011/07/
  19. 19. THANK YOU