1. THERMOCOUPLE
Seebeck effect- when two conductors of dissimilar metels are joined together to form a loop(thermocouple) and two unequal temp are imposed at the two interface connections,an electric current flows through the loop
Peltier effect : a potential difference always exists between two dissimilar metal in contact with each other
Thomson effect : A potential gradient exists even in a single conductor having a temp gradient

2. THERMOCOUPLE MATERIALS

3. DESIRABLE CHARACTERISTICS OF THERMOCOUPLE MATERIAL
The emf produced per degree of temp change must be sufficient to facilitate detection and measurement
Temp- emf relation should be linear
It should maintain calibration without drift for longer period of time
It should be highly resistant to oxidation, corrosion and contamination
It should withstand high and fluctuating temp

4. RESISTANCE THERMOMETER (PLATINUM HAVING POSITIVE THERMAL COEFFICIENT)

5. THERMISTORS (Oxides of copper,nickel,iron,cobalt,uranium etc having negative thermal coefficient)

6. PYROMETER
Pyrometry is a technique for measuring temp without physical contact
It depends upon relationship between the temp of a hot body and electromagnetic radiation emitted by the body
When a body is heated, it emits thermal energy known as ‘radiation’
Pyrometry is the technique for determining body’s temp by measuring its electromagnetic radiation
Types - Radiation and Optical pyrometers

7. RADIATION PYROMETER

8. DISAPPEARING FILAMENT OPTICAL PYROMETER