Question

Example: A type K thermocouple is to be used to measure the temperature of an infant incubator in the Neonatal Intensive Care Unit (NICU). This incubator should be at a temperature of 35 C, and the NICU itself is kept at a temperature of 23 C.

1.
If the incubator is indeed at 35
C, what will the thermocouple
voltage be?
2. If the reference junction of the
thermocouple is placed in an ice
bath, what will the thermocouple
voltage be?

Answer 1

Answer:

Seebeck co-efficient of type K thermocouple is about 41microvolts/deg.C over 0 to 1000 degree C.

Answer 1) When the temperature difference between hot junction and the cold junction is (35-23) = 12 degree centigrade then Vout = 41 * 12 = 492 microvolts or 0.492millivolt approx.   

Answer 2) If the reference junction is at zero degree centigrade then the output voltage from type K thermocuple is:

41*(35-0) = 1435 microvolts or 1.435 millivolts

Hope this helps.