A SEMINAR ON TRANSDUCER PRESENTED BY : SAURABH KUMAR JHANWAR 11ERCEE096
CONTENTS
1) WHAT IS TRANSDUCER2) ELECTRICAL TRANSDUCER3) CLASSIFICATIONS OF TRANSDUCER4) SELECTION CRITERIA OF THE TRANSDUCER5) BASIC CONSTRUCTION OF TRANSDUCER6) RESISTANCE TEMPERATURE DETECTOR7) THERMISTORS8) LVDT9) STRAIN GAUGE10) BOURDON TUBE11) APPLICATION12) ADVANTAGES13) DISADVANTAGES14) CONCLUSION
WHAT IS TRANSDUCER
The transducer is defined as the device which converts the one
form of energy into another form of energy.
Examples:
Temperature transducers
Thermocouples
Resistance-temperature detectors (RTD)
Thermistors
Resistive position transducers
Displacement transducers
Strain gauge
ELECTRICAL TRANSDUCER
The electrical transducers are one which converts the non-electrical quantity into equivalent electrical quantity.
Non-electrical quantity such as force, displacement, stress, temperature.
Electrical quantity such as current, voltage.
CLASSIFICATION OF TRANSDUCERS
On the basis of transduction form used.
As primary and secondary transducers.
As passive and active tranducers.
As analog and digital transducers.
As transducers and inverse transducers.
ON THE BASIS OF TRANSDUCTION FORM USED
Resistive transducers.
Capacitive transducers.
Inductive transducers.
Voltage and current generating transducers.
PASSIVE AND ACTIVE TRANSDUCERS
If transducers derive the power require for transduction from an auxiliary power source, then this kind of transducer are known as passive transducer.
Example
LVDT
RVDT
When there is no need for any source then these type of transducers are active transducers.
Example
Thermocouple
Piezoelectric crystal
ANALOG AND DIGITAL TRANSDUCERS
Analog transducers convert the non-electric (physical quantity) into
an analog output which is a continuous function of time.
Example:
Strain gauge
LVDT
Thermocouple
Whereas digital transducers convert the physical quantity into the
form of pulse.
TRANSDUCERS AND INVERSE TRANSDUCERS
A transducer can be broadly defined as a device which converts a
non-electrical quantity into an electrical quantity.
While inverse transducers convert a electrical quantity into non
electrical quantity.
Example:
Analog ammeter
voltmeter
SLECTION CRITERIA OF THE TRANSDUCERS
Operating principle
Sensitivity
Operating range
Accuracy
Errors
Environmental capability
Insensitive to unwanted signal
stability
BASIC CONSTRUCTION OF TRANSUCERS
It consists of two important parts:
Sensing or detector element
Transduction element
RESISTANCE TEMPERATURE DETECTOR
It is used for measurement of small temperature difference as well as for wide ranges of temperature.
THERMISTORS
These are actually the “thermal resistors” and used for precision temperature measurement, control and compensation.
LVDT
Used for measuring linear displacement (position).
have low hysteresis and excellent repeatability.
converts a position or linear displacement from a mechanical reference (zero, or null position) into a proportional electrical signal containing phase (for direction) and amplitude (for distance) information.
STRAIN GAUGE
It works on Piezoresistive effect.
These are used for measurement of stress and strain
If an elastic material is subjected to tension then its resistance changes.
BOURDEN TUBE
Curved metallic tubes with
Elliptical cross section
Sealed at one end
Tends to straighten when pressure applied
Angular sensitivity proportional to pressure applied
APPLICATION
Measurement of Temperature (RTD, Thermocouple)
Measurement of pressure (Bourdon tubes)
Measurement of Acceleration (Piezoelectric Crystal)
Measurement of Flow ( Electromagnetic Flow Meter)
Measurement of Displacement (LVDT, Capacitance Transducer, Strain Gauge)
Transducers are used in electronic communications systems to convert signals of various physical forms to electronics signals , and vice versa. In this example, the first transducer could be a microphone, and the second transducer could be a speaker.
ADVANTAGES
Power requirement is very low for controlling the electrical or electronic system.
Output can be indicated and recorded remotely from the sensing element.
Electrical amplification and attenuation can be easily done.
An amplifier may be used to amplify the electrical signal according to requirement.
DISADVANTAGES
RTD produce mechanical vibrations
Their cost is high.
Thermistors are unsuitable for wide temperature.
Relative large displacement is required for appreciable output for LVDT.
Bourdon tube do not provide the precise measurement.
CONCLUSION
Transducers are used to convert one form energy to another.
All the transducers are very useful in all the application such as microphone, speakers etc.
REFERENCES
en.wikipedia.org/wiki/Transducer
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