Physics Dept. Demonstration Manual

DHT12 - Thermocouple

Objective: To show that an emf is generated when the junction of two differing metals is heated.

 

Apparatus:  
  • Copper - constantan thermocouple (pair in series)
  • Ice bath (300 ml Beaker)
  • Fluke voltmeter
  • Matches



Method:

One thermocouple is kept at Ice temperature, and an initial measurement of emf potential is made. Then the "free" thermocouple is heated (fingers, then match). An increased potential on the meter shows an electron flow due to the differing electron activity of the two metals.

Note:

Constantan Alloy: 60% copper, 40% Nickel