Question

Questions: After the voltmeter is shorted to zero, connect the thermocouple, check that the cold end is at 0 °C, the hot end is in the air, and record the Voltage data after stabilization. Connect the thermocouple hot-end cable to the tune connection in opposite sequence, record the Voltage data after stabilization, search for the thermocouple related principle, and analyze the reasons for the difference between the two sets of data.

Answer 1

A thermocouple is the combination of two metals joined together form two junction. one is connected to the body whose temperature is to be measured, this is not measuring junction. the other junction is connected to a body of known temperature, this is the cold or reference junction. working principle for this are (i) seeback (ii) peltier (iii) Thomson ellets.

1) Seeback :- The seeback effect states that when two different or unlike metals are joined together at two junction, an emf is generated at the two junctions the amount of emf is different