Type J Thermocouple: The type J is also very common. It has a smaller temperature range and a shorter lifespan at higher temperatures than the Type K. It is equivalent to the Type K in terms of expense and reliability.
Type J Temperature Range:
Thermocouple grade wire, -346 to 1,400F (-210 to 760C)
Extension wire, 32 to 392F (0 to 200C)
Type J Accuracy (whichever is greater):
Standard: +/- 2.2C or +/- .75%
Special Limits of Error: +/- 1.1C or 0.4%
Consideration for bare wire type J thermocouple applications:
The Type J Is Well Suited To Oxidizing Atmospheres
Type K Thermocouple (Nickel-Chromium / Nickel-Alumel): The type K is the most common type of thermocouple. It’s inexpensive, accurate, reliable, and has a wide temperature range. The type K is commonly found in nuclear applications because of its relative radiation hardness. Maximum continuous temperature is around 1,100C.
Type K Temperature Range:
Thermocouple grade wire, –454 to 2,300F (–270 to 1260C)
Extension wire, 32 to 392F (0 to 200C)
Type K Accuracy (whichever is greater):
Standard: +/- 2.2C or +/- .75%
Special Limits of Error: +/- 1.1C or 0.4%
Type of K Thermocouple
Consideration for bare wire type K thermocouple applications: