Piezo-Electric Transducer

Definition

What is Piezo-Electric Transducer?

 

The Piezoelectric transducer is a transducer used for conversion of pressure or mechanical stress into an alternating electrical force.

It is used for measuring the physical quantity like force, pressure, stress, etc., which is directly not possible to measure.

The piezo transducer converts the physical quantity into an electrical voltage which is easily measured by analogue and digital meter.

The piezoelectric transducer uses the piezoelectric material which has a special property, i.e. the material induces voltage when the pressure or stress applied to it. The material which shows such property is known as the electro-resistive element.

The word piezoelectric means the electricity produces by the pressure. The Quartz is the examples of the natural piezoelectric crystals, whereas the Rochelle salts, lithium sulphate, dipotassium tartrate are the examples of the man made crystals.

Piezoelectric Effect

The EMF develops because of the displacement of the charges. The effect is changeable, i.e. if the varying potential applies to a piezoelectric transducer, it will change the dimension of the material or deform it. This effect is known as the piezoelectric effect.

The pressure is applied to the crystals with the help of the force summing devices for examples the stress is applied through mechanical pressure gauges and pressure sensors, etc. The deformation induces the EMF which determines the value of applied pressure.

Application of Piezoelectric Materials

• In microphones, the sound pressure is converted into an electric signal and this signal is ultimately amplified to produce a louder sound.
• Automobile seat belts lock in response to a rapid deceleration is also done using a piezoelectric material.
• It is also used in medical diagnostics.
• It is used in electric lighter used in kitchens. The pressure made on piezoelectric sensor creates an electric signal which ultimately causes the flash to fire up.
• They are used for studying high-speed shock waves and blast waves. Used in fertility treatment.
• Used in Inkjet printers
• It is also used in restaurants or airports where when a person steps near the door and the door opens automatically. In this, the concept used is when a person is near the door pressure is exerted person weight on the sensors due to which the electric effect is produced and the door opens automatically.

Piezoelectric Transducer Advantages

• No need for an external force
• Easy to handle and use as it has small dimensions
•  High-frequency response it means the parameters change very rapidly

 

Piezoelectric Transducer Disadvantages

•  It is not suitable for measurement in static condition 
• It is affected by temperatures
• The output is low so some external circuit is attached to it
• It is very difficult to give the desired shape to this material and also desired strength