This document discusses various types of transducers. It begins by defining transducers as devices that convert one form of energy into another. Sensors and actuators are described as input and output transducers, and can be either analog or digital. The document then discusses factors like ruggedness, linearity, and dynamic response that are important in transducer selection and design. Examples of specific transducer types discussed include bourdon tubes, bellows, strain gauges, thermistors, and digital encoding transducers.

1. Sheela.P
Lecturer / EEE

2. Proud to be a Electrical
Engineer
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3. Sensor Technology
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4. TRANSDUCER
• Transducers convert one form of energy into
another
• Sensors/Actuators are input/output transducers
• Sensors can be passive (e.g. change in
resistance) or active (output is a voltage or
current level)
• Sensors can be analog (e.g. thermocouples) or
digital (e.g. digital tachometer)
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5. Necessity of Transducer
 Ruggedness
 Linearity
 Repeatability
 High Stability and Reliability
 Good Dynamic Response
 Convenient Instrumentation
 Residual Deformation
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6. Selection of Transducer
• Physical quantity to be measured
• Transducer principle –suitable for the quantity
to be measured
• Accuracy in the measurement
• I/O characteristics transducer with the recording
system
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7. Advantages of Transducer
• Amplification and Suppression can be done
easily.
• Mass-inertia effects are minimum
• No friction effects present during –indication
quantity.
• Measuring systems controlled with least power.
• Output can be easily received, transmitted &
processed before measuring.
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8. Sensing Element
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9. Sensing Element
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10. Active Transducer
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11. Passive Transducer
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12. Active & Passive
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13. Analog Transducer
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14. Digital Transducer
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15. Bourdon Tube
• Bourdon tubes are known for its very high
range of differential Pressure Measurement in
the range of almost 100,000 psi (700 Mpa).
• It is an elastic type Pressure transducer.
• Eugene Bourdon in the year of 1849.
• Various forms
 C type
 Spiral
 Twisted Tube
 Helical
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16. Bourdon Tube
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17. Bourdon Tube Working
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18. Bourdon Tube
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19. Bellows
• Bellows is used for pressure measurement, can
be made up of cascaded capsules.
• Expanded or contracted axial by changes in
pressure.
• Materials Commonly used :
 Brass
 Bronze
 Beryllium copper
 Alloys of nickel & copper
 Steel
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20. Bellows
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21. Bellows Working Principle
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22. Load Cells
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23. Strain Gauges:
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24. Strain Gauge Working Principle
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25. Thermistor
• Thermal Resistors- Semi conductor device.
 Negative Temperature Coefficient
 Positive Temperature Coefficient
• Room Temperature resistorΩ is 100 Ω to
10M Ω normally at 80 C⁰
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26. Types of Thermistor
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27. PTC & NTC
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28. Metal Resistance Thermometer
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29. Digital Encoding Transducer
• A digital optical encoder is a device that
converts motion into a sequence of digital
pulses.
• By counting a single bit or by decoding a set of
bits, the pulses can be converted to relative or
absolute position measurements.
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30. Shaft Encoder
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31. Optical Encoder
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