Eureka is a commercial name of a heating element whose composition is:

Eureka:

• Constantan is a Nickel-Copper alloy also known as Eureka.
• It usually consists of 55% copper and 45% nickel.
• Its main feature is the low thermal variation of its resistivity, which is constant over a wide range of temperatures
• Constantan is a Nickel-Copper-based alloy wire that has a high resistivity and is mainly used for thermocouples and electrical resistance heating.
• It has a constant resistivity over a wide range of temperatures.
   

Composition:

• Ni = 45 %
• Cu = 55 %
   

Properties of Eureka:

• Resistivity - 490 µΩ -cm
• Melting point: 1300 ⁰C
• Specific gravity: 8.9 gm /cm³
• Negligible temperature Coefficient
• Easily ductile
• Resistant to atmospheric corrosion
• Can be easily soldered and moulded
   

Application:

• It is used for the measurement of temperature.
• It is used for the formation of thermocouple, along with the wires of other metals such as copper, iron, and chromium.
• It is especially used for resistance purposes since its resistance does not change much with the change in its temperature. It is used for DC current shunts.