Abstract: The fixed constant excitation current direction is widely used in RTD temperature measurement system. Usually the temperature is measured by measuring the resistance of RTD which is gauged from potential difference. The system is always affected by the thermoelectric potential. The measured resistance of RTD is different from the actual data, which will affect the temperature measurement results. The mechanism of thermoelectric potential which impacts on the results of the temperature measurement in the circuit is analyzed and the analytical results are verified by experiment. The recommendation and guidance of reducing or eliminating the impact of the thermoelectric potential difference on the results of temperature measurement are proposed.

Key words: Temperature, Thermoelectric potential, Measurement