‘Transducer' is 'a device that transfers power
from one system to another in the same or in
the different form'.
DEFINING A TRANSDUCER
Device that converts one type of energy or signal
• A microphone is a transducer that converts
sound waves into electric impulse.
• An electric motor is a transducer that converts
electricity into mechanical energy.
• Transducers are widely used in measuring
• Sensors have an important role in transducer.
• Sensor is used to detect a parameter in one form
and report it in another form of energy.
• Most of the transducer either convert electrical
energy into mechanical or convert non electrical
physical quantity to an electrical signals.
A transducer which measures physical quantity
and transmits the information as coded digital
signal is known as a ‘ Direct Digital Transducer’.
Most transducers used in digital systems are
primarily analogue in nature
They are incorporated with some form of
conversion to provide the digital output.
Provides o/p signal in the form of rectangular
pulses of constant duration and amplitude.
Measures physical quantities and transmits
the information as coded.
Most of the signals are continuously varying
•Provides ease of generating
•Ease of manipulating
•Strong digital signals
•Great accuracy and discrimination
•Gives simplified data presentation
•It supports high level digital signal to external
disturbances so transmitting signal over long
A Strain Gauge is a device used to measure strain on
•It converts force, pressure, tension, weight, etc.,
into a change in electrical resistance which can
then be measured.
When a metal conductor is stretched or compressed,
Its resistance will also get changed.
Works based on electrical measurement technique.
Types of strain gauge
•Wire wound strain gauge
•Foil type strain gauge
•Semiconductor strain gauge
•Capacitive strain gauge
•Consist of a insulating flexible backing which
supports metallic foil pattern.
• The gauge is attached to suitable adhesive called
•As the object is deformed the foil is deformed,
causing the electrical resistance to change.
•It converts force, pressure, tension, weight etc into
a into electrical resistance which can then
be measured in desired quantities.
•These gauges have a high gauge factor
•Excellent hysteresis characteristics
•Gauges are very sensitive to changes in
•Linearity of these gauges is poor