What is the Cold Junction in a thermocouple?

What is the Cold Junction in a thermocouple?

• A. Hot Junction
• B. Cold Junction
• C. Junction point
• D. Reference point

Answer: (B)

In a thermocouple, the voltage you measure comes from the temperature difference between the two junctions. The Cold Junction is the end connected to the measuring instrument, where the temperature is known and used as the reference. This end is typically at ambient temperature, and the instrument applies cold-junction compensation to translate the measured EMF into the actual temperature at the hot junction. Historically a 0°C ice bath was used, but modern devices do the compensation electronically. This end is the reference, not the hot junction itself.

In a thermocouple, the voltage you measure comes from the temperature difference between the two junctions. The Cold Junction is the end connected to the measuring instrument, where the temperature is known and used as the reference. This end is typically at ambient temperature, and the instrument applies cold-junction compensation to translate the measured EMF into the actual temperature at the hot junction. Historically a 0°C ice bath was used, but modern devices do the compensation electronically. This end is the reference, not the hot junction itself.