piezoelectricity explained for science students with its application in real world

1. By:
MAANYA JOHRI
XI-B
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2. 2MAANYA JOHRI XI-B

3. 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
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4. 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)
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5. 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.
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6. Fig: (a) Random orientation of domains prior to poling
(b) Poling in DC ElectricField
(c) Remanent polarization after field is removed
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POLING

7. CONTINUED
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.
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8. PIEZO TRANSDUCER
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9. PIEZOELECTRIC
ENERGY HARVESTING
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POWER GENERATING SIDEWALK

11. 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 inthe
vehicle like clutches, gearsetc.
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12. 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.
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13. Idea was researched in
US.
To power the battlefield
equipment by generators
embedded in soldier boots.
Idea was abandoned due
to the discomfort.
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POWER GENERATING BOOTS OR
SHOES

14. 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. 14MAANYA JOHRI XI-B

15. 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.
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16. 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.
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17. ADVANTAGES DISADVANTAGES
Unaffected by external
electromagnetic fields.
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.
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18. 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.
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19. BIBLIOGRAPHY
:“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.e
etimes.com/electronics-news/4197064/Piezoelectric-
Technology-A-Primer)
http://www.instrumentationtoday.com/piezoelectric-
transducer/2011/07/
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20. THANK
YOU
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