Thermocouple

As the generated voltage in the thermocouple circuit depends upon the difference of temperature between the hot and cold junction of the thermocouple, the accuracy of the measured temperature of junction depends on keeping the other junction at a known constant temperature. The temperature in the connection cap isn’t constant. For this reason the legs of the thermocouple are extended by means of COMPENSATING CABLE LEADS made of material which will not produce, in junction with the thermocouple metal, any additional voltage. Thus the COMPENSATING CABLE LEADS effectively extends the junctions of the thermocouple to a convenient point of constant temperature ensuring the accuracy of the measured temperature for which the thermocouple is used
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