"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: Nia 55%: 45%. Although EN, TN, JN are all called Constantan, EN and TN don not give the same EMF output curve