This document discusses temperature measurement and different temperature scales. It describes common temperature measurement devices including expansion thermometers, thermocouples, RTDs, thermistors, integrated circuits, optical pyrometers, and infrared thermometers. Expansion thermometers like mercury and alcohol thermometers measure temperature by detecting the thermal expansion of liquid. Thermocouples use the Seebeck effect to convert temperature differences to voltage. RTDs measure resistance changes in materials like platinum to determine temperature.

2. TEMPERATURE MEASUREMENT
AND ITS SCALE

3. GROUP MEMBERS
• Nauman Aslam 13-ME-47
• Raja Sami 13-ME-49
• Rameez Raja 13-ME-51
• Saeed Anwar 13-ME-53
• Shshbaz Haider 13-ME-55

4. TEMPERATURE
• Definition
 Correlates to molecular kinetic energy

5. TEMPERATURE
 Units
 Centigrade (C)
 Fahrenheit (F)
 Kelvin (K)
• Symbol
 T

6. TEMPERATURE MEASURING
SCALES
• Centigrade
 Denoted by °C
 Water freezes at O°C and boils at 100°C
• Fahrenheit
 Denoted by °F
 Water freezes at 32°F and boils at 212°F
• Kelvin
 Denoted by K
 Water freezes at 273K and boils at 373K

7. INTER CONVERSION
• C to F
• F=9/5C+32
• F to C
• C=5/9(F-32)
• C to K
• K=c+273

8. TEMPERATURE MEASUREMENT
• Expansion thermometers
• Thermocouples
• RTDs (Resistive Temperature Devices)
• Thermistors
• Integrated Circuits
• Optical pyrometers
• Infrared thermometers

9. EXPANSION THERMOMETER
• Expansion thermometers
• Common
• Inexpensive
• Huge thermal mass
• Very slow to respond

10. EXPANSION THERMOMETER
• Mercury glass thermometer
• Thermal expansion
• Commonly used in clinics

11. EXPANSION THERMOMETER
• Alcohol thermometer
• Thermal expansion
• Commonly used in Labs

12. BI METALLIC STRIP THERMOMETER
• Bimetallic strip thermometers
• Dial
• Convenient
• Inexpensive
• Poor accuracy and precision

13. THERMOCOUPLES
• Two different metals are joined together
• Change in temperature cause magnetic field
• Seekbeck effect
• Voltage can be interpreted in readable temperature

14. THERMOCOUPLES
• Seebeck Effect
• Any conductor subjected to a temperature gradient generates a potential difference
• Working principle of thermocouples

15. THERMOCOUPLES
• Type K
• the most common general purpose thermocouple
• −200 °C to +1350 °C
• constituent metals is Nickel
• Cause magnetic field @ curie temperature
• @ 354 °C.

16. THERMOCOUPLES
• Type E
• It is non-magnetic.
• Cryogenic use
• 68 µV/°C
• Type J
• Less popular then K type
• −40 to +750 °C
• 50 µV/°C
• The Curie point of the iron 770 °C

17. COMPARISON

18. RTD
• Electronic technology
• resistance temperature detectors
• correlating the resistance
• element is usually quite fragile
• Pure material, typically platinum, nickel or copper
• slowly replacing the use of thermocouples (<600 C)

19. RTDS TYPE
• wire wounded
• Coil and type

20. RTDS TYPE
• Thin film type

21. THERMISTORS
• Resistance is dependent on temperature
• ceramic or polymer
• −90 °C to 130 °C

22. THERMISTOR TYPES
• Positive temperature coefficient (PTC)
• Negative temperature coefficient (NTC)
• Silistor

23. COMPARISON

24. IC TEMPERATURE SENSORS
• Two terminal integrated circuit
• Produce an output current
• Sensor package is small
• low thermal mass and a fast response
• 55 to 150°C

25. COMPARISON

26. OPTICAL PYROMETER
• Body of interest must emit in the visible
• Ancient technology
• Temperature measured at least 650 C

27. INFRARED THERMOMETERS
• Thermal detectors
• Bolometers, pyroelectric detectors
• Radiation causes temperature of detector to rise