PIEZOELECTRIC TRANSDUCERByPRADEEP SENTHIL

TRANSDUCERA transducer may be defined as a device that

converts energy from one form to another form.Energy transmission can be electrical ,

mechanical , or a combination of any two or more It is often very convenient to make measurements

in terms of electrical quantities such as voltage or current and easy in recording, storing ,and transmission of these electrical quantities.

PIEZOELECTRIC PRESSURE TRANSDUCERS

• These device utilize the piezoelectric characteristics of certain crystalline and ceramic materials (such as quartz) to generate an electrical signal.

PRINCIPLEWhen pressure is applied on crystal , an electrical charge is

generated.Some of the piezoelectric materials are barrium titanate

sintered powder , crystal of quartz , tourmaline, and rochelle salts. •  If a mechanical strain is given along the Y-axis, electrical charges will be produced On the faces of the crystal, perpendicular To the x-axis which is at right angles to the Y-axis.

CONSTRUCTION AND WORKINGIt consists of a diaphragm by which pressure is transmitted

to the piezoelectric crystal y1. This crystal generates an electrical signal which is amplified by a charge amplifier.

A 2nd piezoelectric crystal y2 is included to compensate for any acceleration of the device during use.

APPLICATION• It is used in ultrasonic , non destructive test

equipment , ultrasonic flowmeter.• It is used in non electrical quantities such as

acceleration, vibration, dynamic pressure.• It is used in bomb explosion due to increasing the

pressure.

ADVANTAGESVery high frequency response.Self generating, so no need of external source.Simple to use as they have small dimensions and

large measuring range.

DISADVANTAGESIt is not suitable for measurement in static condition.Since the device operates with the small electric

charge, they need high impedance cable for electrical interface.

The output may vary according to the temperature variation of the crystal.