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.

1. By:
AZEEM AHMAD KHAN
ELECTRONICS ENGG.
A4LE 44
Under the Guidance of :
Prof. MJR Khan Sb.

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).

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)

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.

6. Contd.
Fig: (a) Random orientation of domains prior to poling
(b) Poling in DC Electric Field
(c) Remanent polarization after field is removed

7. 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.

8. PIEZO TRANSDUCER

9. PIEZOELECTRIC ENERGY HARVESTING

10. 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 in
the vehicle like clutches,
gears etc.

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.

13. 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.

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.

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.

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.

17. 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.

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.

19. 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/

20. THANK
YOU