Piezo electricity is defined as a change in electric
polarisation with a change in applied stress.
The word piezo is Greek for "push“.
Crystals which acquire a charge when compressed,
twisted or distorted are said to be piezoelectric. This
provides a convenient transducer effect between
electrical and mechanical oscillations.
The converse of piezo electric effect is the change of
strain or stress in a material due to an applied electric
It was discovered in 1880 by Jaques and Pierre Curie
during studies into the effect of pressure on the
generation of electric charge by crystals
(such as quartz)
• The effect is explained by the displacement of ions in
crystals that have a nonsymmetrical unit cell
• When the crystal is compressed, the ions in each unit
cell are displaced, causing the electric polarization of
the unit cell.
• Because of the regularity of crystalline structure,
these effects accumulate, causing the appearance of
an electric potential difference between certain faces
of the crystal.
• When an external electric field is applied to the
crystal, the ions in each unit cell are displaced by
electrostatic forces, resulting in the mechanical
deformation of the whole crystal.
• In simple words, Piezoelectric materials are
crystalline solids whose asymmetric structures create
an electric dipole moment in the crystal lattice, which
is sensitive to both elastic strain and applied
• When an electrical field is applied to a piezoelectric
material, a stress is induced and the material changes
shape (called the piezoelectric effect).
Examples of piezo electric
Piezoelectric materials can be divided in 2 main groups:
crystals and ceramics.
Barium Titanate BaTiO3
Lead Zirconate Titanate PZT
Polyvinylidene DiFluoride PVDF
Working of quartz crystals
Quartz crystals have piezoelectric properties, meaning
that they are capable of changing a mechanical force
into electricity, or an electric current into a mechanical
force. A slice, or wafer, of quartz crystal will generate
an electric current when it is subjected to pressure.
Working of quartz crystals
This property is used in quartz watches and
clocks,which have an accuracy of one second in every 10
The reverse piezoelectric effect is utilised in printing equipment,
both in the home and on industrial production lines.
Simple speakers,watch beepers, portable stereo systems, and in
mobile phones and computers.
In ultrasonic transducers, used for medical ultrasound imaging
TV remote controls and echolocation devices used to help
drivers park their car.
Piezoceramic filters are used in:
Radios and televisions
Battery operated smoke detector alarms
• Have a high Stiffness value and
produce a high output with very little
• Ideal for rugged use.
• Excellent linearity over a wide
• Ideal for continuous online condition
monitoring smart systems.
•Can be used only for dynamic
pressure sensing as in case of static
sensing the signals will decay away
•Operation over long cables may
affect frequency response and
introduce noise and distortion, the
cables need to be protected.
• New applications and potential uses of piezoelectric
components are being identified in a number of different fields.
• Piezoelectric components’ durability and low cost mean that as
research and development continues, the range of commercial
applications will also continue to grow rapidly.
• The market for piezoelectric components is expected to see
double digit growth in the next five years. New devices such as
piezoelectric generators will see the highest growth, estimated
at 51.5% annually.