NiCr- CuNi thermocouple (type E) is also named NiCr- Constantan thermocouple. The main chemical composition of positive leg NiCr (EP) is Ni: Cr≈90:10; negative leg Constantan (EN) is Cu: Ni≈ 55%: 45%. Although EN, TN, JN are all called Constantan, EN and TN don not give the same EMF output curve as JN. EN and TN are able to interchange but they are not interchangeable with JN. The operating temperature range of type E thermocouple is -200~900℃.