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Contents

*Introduction *Internal working*Configurations*Pros and Cons*Applications

Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress.

What is piezo electric ?

ROOT!

PiezoelectricityGreek root Latin root

“piezein” to press “Electrum”amber

DISCOVERYDiscovered in 1880 by brothers Pierre and Jacques Curie in quartz crystals

Developing theories… Pierre and Jacques Curie predicted and

demonstrated the piezoelectric effect using tinfoil, glue, wire, magnets.

They showed that crystals of tourmaline, quartz, topaz, and Rochelle salt generate electrical polarization from mechanical stress.

The converse effect was mathematically derived by Gabriel Lippman in 1881 using fundamental thermodynamic principles and was later experimentally confirmed by the Curies.

Chemical Composition: SiO2 (Silicon Dioxide)Color(s): Clear, White, Pink Brown, Gray, Black, Green, Blue, Orange, Yellow (Citrine), Purple Lustre: VitreousTransparency: Transparent, Translucent

Types of Piezoelectric Materials

Naturally occurring crystals: cane sugar, Quartz, Rochelle salt, Topaz, Tourmaline Group Minerals, and dry bone (apatite crystals)

Man-made crystals: Gallium orthophosphate (GaPO4), Langasite (La3Ga5SiO14)

Man-made ceramics: Barium titanate (BaTiO3), Lead titanate (PbTiO3), Lead zirconate titanate (Pb[ZrxTi1-x]O3 0<x<1) - More commonly known as PZT, Potassium niobate (KNbO3), Lithium niobate (LiNbO3), Lithium tantalate (LiTaO3), Sodium tungstate (NaxWO3), Ba2NaNb5O5, Pb2KNb5O15

Polymers:Polyvinylidene fluoride (PVDF)

P.E.E and Inverse P.E.E

mechanical distortion

Internal working 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.

Piezoelectricity displacement of

electrical charge due to the deflection of the lattice in a naturally piezoelectric quartz crystal

The larger circles represent silicon atoms, while the smaller ones represent oxygen.

Quartz crystals is one of the most stable piezoelectric materials.

Configurations Red indicates the

crystal Arrows indicate the

direction of applied force

the compression design features high rigidity, making it useful for implementation in high frequency pressure and force sensors

Configurations Grey- test structure. Red- piezoelectric

crystals Blue- Sensor housing The black electrode is

where the charge from the crystals accumulates before it is conditioned by the yellow, micro-circuit.

pressure sensors utilize a diaphragm to collect pressure, which is simply force applied over an area.

Pros and Cons Have a high Stiffness

value and produce a high output with very little strain.

Ideal for rugged use. Excellent linearity

over a wide amplitude.

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.

Sonic and Ultrasonic Applications

Sonar with Ultrasonic time-domain reflectometers

Materials testing to detect flaws inside cast metals and stone objects as well as measure elasticity or viscosity in gases and liquids

Compact sensitive microphones and guitar pickups.

Loudspeakers

A voice from the electricity phenomenon of piezoelectricity, where under the ropes to the mechanical effort especially if it comes to materials such as ceramic or quartz, and lead this gross distortion to the separation of electrical charges within the metal and the occurrence of a difference in the effort leading to the generation of electric current amplifies and converts it to a sound wave through the amplifier sound. This invention in New York City.

Violin

Piezoelectric Igniter

20

Lead zirconate titanate(PZT)

Cigarette Lighters:

22

Time

Motor Applications Piezoelectric elements can be

used in laser mirror alignment, where their ability to move a large mass (the mirror mount) over microscopic distances is exploited. By electronically vibrating the mirror it gives the light reflected off it a Doppler shift to fine tune the laser's frequency.

The piezo motor is viewed as a high-precision replacement for the stepper motor.

Traveling-wave motors used for auto-focus in cameras.