The document discusses piezoelectric transducers, which convert mechanical energy into electrical signals using specific crystalline materials like quartz. These devices apply pressure to generate electrical charges and are widely used in applications such as ultrasonic testing and vibration measurement. While they boast advantages like high frequency response and self-generation, they are unsuitable for static measurements and sensitive to temperature variations.

1. PIEZOELECTRIC
TRANSDUCER
By
PRADEEP SENTHIL

2. TRANSDUCER
A 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.

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

4. PRINCIPLE
When 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.

5. CONSTRUCTION AND WORKING
It 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.

6. 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.

7. ADVANTAGES
Very high frequency response.
Self generating, so no need of external source.
Simple to use as they have small dimensions and large measuring range.

8. DISADVANTAGES
It 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.