Editing Constantan (section)

{{Short description|Alloy of copper and nickel}}
{{Infobox material
| name = Constantan
| image = Konstantandraht.jpg
| image_size = 
| alt = 
| caption = A spool of Constantan wire
| type = Copper-nickel alloy
| density = {{convert|8885|kg/m3|g/cm3|disp=out}}
| youngs_modulus = 162 GPa
| tensile_strength = ~450 MPa
| elongation = ~0.25%
| melting_point = {{val|1210|u=degC}}
| thermal_conductivity kg·K)
| dielectric_constant_note = 
| dielectric_constant = 
| permittivity = 
| relative_permeability_note = 
| relative_permeability = 
| permeability_note = 
| permeability = 
| surface_resistivity = 0.56 μΩ·m
| volume_resistivity = 
}}

'''Constantan''', also known in various contexts as Eureka, Advance, and Ferry, refers to a copper-nickel alloy commonly used for its stable electrical resistance across a wide range of temperatures.<ref>{{cite book |url=https://books.google.com/books?id=5jOblzV5eZ8C&pg=SA10-PA43 |title=Electrical Engineers Reference Book |edition=16th |year=2003 |author=M. A. Laughton |author2=D. F. Warne |publisher=Elsevier |isbn=0-7506-4637-3 |page=10/43}}</ref> It usually consists of 55%&nbsp;copper and 45%&nbsp;nickel.<ref name=Davis158>{{cite book |author=J. R. Davis |title=Copper and Copper Alloys |publisher=ASM International |year=2001 |isbn=0-87170-726-8 |page=158}}</ref> Its main feature is the low thermal variation of its [[resistivity]], which is constant over a wide range of temperatures. Other [[alloy]]s with similarly low [[temperature coefficient]]s are known, such as [[manganin]] (Cu [86%] / Mn [12%] / Ni [2%] ).