Piezoelectricity & Its Applications
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Transcript of Piezoelectricity & Its Applications
PIEZOELECTICITY AND ITSAPPLICATIONS
By:AZEEM AHMAD KHANELECTRONICS ENGG.
A4LE 44
Under the Guidance of :
Prof. MJR Khan Sb.
CONTENTS
1.INTRODUCTION2.MATERIALS3.WORKING4.APPLICATIONS5.CONCLUSION
INTRODUCTIONPiezoelectricity 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).
MATERIALSNATURAL 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)
WORKINGThe 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.
Contd.
Fig: (a) Random orientation of domains prior to poling (b) Poling in DC Electric Field (c) Remanent polarization after field is removed
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.
PIEZO TRANSDUCER
PRIME APPLICATION
PIEZOELECTRIC ENERGY HARVESTING
POWER GENERATING SIDEWALK
GYMS AND WORKPLACESVibrations 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.
MOBILE KEYPADS & KEYBOARDSCrystals laid down under
keys of mobile unit and keyboard.
For every key pressed vibrations are created.
These vibrations can be used for charging purposes.
POWER GENERATING BOOTS OR SHOESIdea was researched in
US.To power the battlefield
equipment by generators embedded in soldier boots.
Idea was abandoned due to the discomfort.
FLOOR MATS AND PEOPLE POWERED DANCE CLUBSSeries 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.
OUTPUT POWERThe 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.
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.
ADVANTAGES DISADVANTAGESUnaffected by external electromagnetic fields.
They cannot be used for truly static measurements
Pollution FreeCan 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.
CONCLUSIONPiezoelectricity 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.
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/piezoelectricity-design-notes.
(http://web.archive.org/web/20101006002651/http://www.eetimes.com/electronics-news/4197064/Piezoelectric-Technology-A-Primer)
http://www.instrumentationtoday.com/piezoelectric-transducer/2011/07/
THANK
YOU