Reference Junction Units- WHY?

1. Thermocouple output is dependent of temperature of hot junction and temperature of cold junction.
2. The Cold junction temperature needs to be known to get the hot junction temperature.
3. To reduce the uncertainity of cold junction measurement Reference junction boxes are used.
4. A reference junction box terminates the thermocouple cold end at a known and constant temperature. This can be 0 deg or 60 Deg C, as per user requirement.
5. The EMF of the reference junction is fixed and is added on to the output of the thermocouple.