Regarding Industrial Instrumentation and EMMI.

1. Module 5
Transducer
Prof. Amit A. Kulkarni
Electrical Engineering Department
B.H.Gardi College of Engineering and Technology

2. • Definition
• Types
• Selection Criteria
• Characteristics
• Displacement measurement
• Speed measurement
• Force measurement
• Torque measurement
• Humidity and Moisture measurement
• Pressure, Strain measurement
• Temperature measurement
• Instrumentation amplifiers
• Digital methods

3. Definition
• An electronic instrumentation system consists
of a number of components to perform a
measurement and record its result.
• A device which Transforms signal from one
form to another.
• Input
Non-electrical quantity.
• Signal Conditioning
Amplification
Attenuation
Filtered
Modulation
Modified
• Output
• Display
Input
Non-electrical Quantity
Signal
Conditioning
Output
device

4. Types
Transducer
Quantity
measured
Temperature
transducer
Pressure
Displacement Flow
Others
Principle of
Operation
Hall effect Piezo
Electromagnetic Ultrasonic
Doppler
Application
Commercial Residential
Industrial Testing
Excitation
source
Active
Transducer
Passive
Transducer

5. • Active Transducer:
• Those transducer which do not
need any external source of
power for their operation.
• Self Generating type.
• Output ∝ Potential.
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T
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Photovoltaic
Thermoelectric
Piezoelectric
Electromagnetic
Chemical
Others
Based on Excitation

6. Based on Excitation
• Passive Transducer:
• Those transducer which
need an external source
of power for their
operation.
• Not Self Generating
type.
• DC power supply or an
audio frequency
generator used as an
external power source.
• Output ∝ Potential.
Passive Transducer
Variable Resistance
Strain Gauge
Thermistor
Potentiometric
Photoconductor
Variable
Reactance
Inductive
Variable Reluctance
Variable Permeability
LVDT
Capacitive
Change in Area
Change in distance
between plates
Optoelectronic
Photo emissive
Photo
conductive
Hall effect type

7. Active
Transducer
Do not need
external
power supply.
Self
Generating
Output
proportional
to V, I
Eg.
Thermocouple,
piezoelectric
Comparison
Passive
Transducer
Need external
power supply
Produce
variation in R,
L, C
Eg. Thermistor,
LVDT.

8. • Temperature measurement.
Based on Quantity being measured

9. Based on Quantity being measured
• Pressure measurement.

10. • Displacement measurement.
Based on Quantity being measured

11. • For a transducer under any application it must posses:
• Input Characteristics.
• Transfer Characteristics.
• Output Characteristics.
Selection Criteria
Input
Element
Transformation
(Physical→Electrical)
Electrical
Output
Signal

12. • Types of input and Operating range:
• Identify the nature of quantity
• Find range of magnitude and frequencies which it persists.
• Loading Effects:
• Transducer selected for a particular application should ideally extract no force, power or
energy from measurand so that latter is measured accurately.
Input Characteristics

13. • Transfer Function
• Error
• Scale Error
• Zero Error
• Non-conformity
• Noise and Drift Error
• Frequency Error
• Environmental Changes
Transfer Characteristics

14. • Type of electrical output.
• Output Impedance.
• Useful output Impedance.
Output Characteristics

15. • Operating Principle.
• Operating Range.
• Sensitivity.
• Accuracy.
• Errors.
• Environment.
• Loading effect.
• Stability and Reliability.
• Static Characteristics.
Factors for choice of transducer

16. • Resistive Xducer.
• Potentiometer
• Thermistor
• Strain Gauges
• RTD
• Inductive Xducer.
• Self Inductance
• Change in N.
• Change in Geometric configuration.
• Change in permeability of magnetic circuits.
• Change in Reluctance
• Mutual Inductance
• LVDT
• RVDT
• Capacitive Xducer.
• Change in distance between plates
• Change in area
• Change in di-electric constant K
Passive Transducer

17. • Thermocouples
• Piezoelectric
• Photoelectric
Active Transducer

18. • Low Pressure
• Pirani Gauge
• Mc-leod Gauge
• High Pressure
• R
• L
• C
Pressure Measurement

19. Hall Effect Transducer

20. Instrumentation Amplifier