Thermocouples are classified into various types on the basis of the materials used .The positive and negative leads are composed of metal /matal alloy wires. Specific types of thermocouple are suitable for the use in different conditions and temperature ranges . Let’s see some common types of thermocouple.
Type K
Chromel-Alumel
Composition: Nickel Chromium/Nickel aluminum alloy
Temperature range -200 to1260°C
Suitable for use in oxidising environment
Type J
Iron-Constantan
Composition: Iron/copper nickel alloy
temperature range -40 to 750°C
Type T
Copper-Constantan
Composition:Copper/copper nickel alloy
temperature range -200 to 350°C
It is resistant to moisture.
Type R
Platinum Rhodium(23%)/platinum
Temperature range 1480°C
Type S
Platinum-Rhodium(10%)/platinum
temperature range up to 1600
Type B
Platinum Rhodium(30%)/Platinum Rhodium ( 6%)
Temperature range 0-1700°C
Type N
NicroSil/NiSil
Nickel-chromium-silicon / nickel-silicon-magnesium
temperature range -270°C to 1300°C