The function of the compensation wire for the thermocouple is to extend the cold electrode of the hot electrode, that is, the cold end of the moving thermocouple, and form a temperature measurement system by connecting with the display instrument. The use temperature is between -25 and 200 °C.

Nicrosil-Nisil thermocouple is the latest base metal thermocouple, developed to improve the drawbacks that type K thermocouple has. The main chemical composition of positive leg Nicrosil(NP) is Ni: Cr: Si≈84.4: 14.2: 1.4; negative leg Nisil (NN) is Ni: Si: Mg≈95.5: 4.4: 0.1. Type N thermocouple also be used in the similar atmospheres that type K works, and the operating temperature range is -200~1300℃。 Type N thermocouple improves the EMF drift and short term EMF change, compared to type K thermocouple, and has a longer life than type K thermocouple. Therefore, in the industries where temperature control and measurement are especially critical, type N thermocouple has more advantages than other thermocouple as it has long life and stable thermal EMF.

NiCr-NiSi (Type K) thermocouple finds the widest use in all basemetal thermocouple, at temperature above 500℃。The main chemical composition of positive leg NiCr (KP) are Ni≈90% and Cr≈10%; negative leg NiSi (KN) are Ni≈97% and Cr≈3%. The operating temperature range is - 200~1300℃(for short term) and 0~1100℃( for long term)。 Type K thermocouple has strong resistance to oxidation than other base metal thermocouples. It has high EMF against Platinum 67, excellent temperature accuracy, sensitivity and stability, with a low cost. It is recommended for oxidizing or inert atmospheres, but cannot be used directly in the following cases: (1) Alternatively oxidizing and reducing atmosphere, (2) Atmosphere with sulphur gases (3) Long time in vacuum (4) Low oxidizing atmosphere such as hydrogen and carbon monoxide atmosphere

Nickel-chromium and nickel-chromium-iron alloys are the most widely used high-resistance electrothermal alloys. They have high electrical resistivity, good oxidation resistance and wear resistance, good good machinability and weldability at high temperatures. Have a higher strength. The alloy is suitable for the manufacture of heating elements in metallurgical, chemical, mechanical, glass, ceramic and household appliances industries, voltage regulators and brake resistors of various types of motors.