Constantan is an alloythat consists of the following elements:  Ni (39-41%); Mn (1-2%); all the rest is Cu. This alloy has high electrical resistance (about 0.6 Ohm·m), minimal meaning of the thermal coefficient  of electric resistance, high thermo-electromotive force in a pair with copper, iron and chromel.

A Nickel-Copper alloy wire used mainly for its medium range electrical resistivity and very low temperature-coefficient of resistance.

Applications include power resistors, shunts, thermocouples and wire-wound precision resistors having operating temperatures up to 400 degree.