Thermocouple calculation problems
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1. When using a moving-coil meter equipped with a cold-junction compensator to measure the temperature of a thermocouple, if the temperature of the thermocouple increases by 2°C compared to the room temperature, and the cold-junction temperature decreases by 2°C, then the instrument will indicate ( ). (A) Increase by 2°C (B) Decrease by 2°C (C) Remain unchanged (D) Increase by 4°C. II. When using an electrometric potentiometer to measure the temperature of a thermocouple, if the temperature at the hot end decreases by 2°C and the room temperature (the temperature at the cold end) also decreases by 2°C, then the instrument’s reading will be ( ). (A) Increase by 2°C (B) Decrease by 2°C (C) Remain unchanged (D) Decrease by 4°C. These two questions appear frequently; could someone please provide a detailed explanation? Thank you very much! ! !
1. In case A, there is a compensator at the cold end, so the influence of the cold end on the measurement can be ignored. 2. In case B, the potentiometer has thermocouple cold-end compensation, so the influence of the cold end on the measurement can be ignored