Compensation wire, thermocouple wire pair in the specified temperature range use, it in the prescribed amount within the temperature range of the thermoelectric properties and matching of thermocouple is the same, and is easy to obtain cheap metal materials, as a thermocouple in the temperature measurement and secondary instrument connection wire, the tropical southern end of reference can be moved to the relatively far away from the heat source temperature constant local thermocouple compensating lead wires are in a certain temperature range ( Including room temperature 0) With the matching of the same nominal value thermocouple thermoelectric emfs a pair of wire with insulation layer, use their connection thermocouple and measuring devices, equivalent to extend thermocouple to measure device. Because 'thermocouple compensation wire, in a certain temperature range, Including room temperature 0) With the matching of the same nominal value thermocouple thermoelectric emfs pair wire with insulation layer ', it is can form thermocouple (within a certain range Actually compensation compensating lead wires and the dividing type thermocouple is) with the same material , according to the law of the middle of the thermocouple conductor 'in the middle of the thermocouple loop access conductor ( The third conductor) As long as the middle temperature is the same on both ends of the conductor, the introduction of the center conductor has no effect on the thermocouple loop total potential. That is to say, the influence of excluding thermocouple compensation wire can also produce thermoelectric potential, its size is equal to the temperature difference between the end of a thermocouple and measurement device electric potential. When used properly, the superposition of the electric potential and electric potential compensation conductor thermocouple at the cold end under the condition of constant temperature, as the thermocouple compensating conductor connection and the changes in temperature, thermocouple temperature potential increase compensation conductor of electric potential difference in temperature is reduced, and vice versa, achieve compensation between the thermocouple and measuring device of the impact of changes in temperature. Measurement device produced by the thermocouple wires produce thermoelectric potential and compensation to compensate the potential superposition electric potential.