The resistivity of metals and alloys (at 20° C)

Alloys (composition in %):

• Constantan (58,8 Cu, 40 Ni Of 1.2 Mn)
• Manganin (85 Cu, 12 Mn, 3 Ni)
• Nickel Silver (65 Cu, 20 Zn, Ni 15)
• Nickeline (54 Cu, 20 Zn, Ni 26)
• Nichrome (67,5 Ni, 15 Cr, 16 Fe 1,5 Mn)
• Reonet (84Cu, 12Mn, 4 Zn)
• Resistant (Fe 80, Cr 14, Al 6)

The resistivity of nichrome

Every body through which an electric current, automatically provides him with some resistance. The property of a conductor to resist the electric current is called electrical resistance.

Consider the electronic theory of this phenomenon. When moving through a conductor the free electrons constantly meet on your way other electrons and atoms. Interacting with them, a free electron loses some of its charge. Thus, the electrons encounter resistance from the material of the conductor. Each body has its own atomic structure which provides electric current to different resistance. The unit of resistance is considered to be Ohms. Is indicated strength of materials — R or r.

The smaller the conductor resistance, the easier it is for electric current to pass through the body. And Vice versa: the higher the resistance, the worse the body conducts electricity.

The resistance of each individual conductor depends on the properties of the material from which it is made. For the exact specifications of electrical resistance of a material was introduced to the concept of resistivity (nichrome, aluminum, etc.). Specific is the resistance of a conductor of length 1 m, cross section 1 sq. mm. This figure is designated by the letter p. Each material used in the manufacture of the conductor has its specific resistance. For example, consider the resistivity of nichrome and fehrali (3 mm):

• H15N60 — 1.13 Ohm*mm/m
• KH23JU5T — 1.39 Ohm*mm/m
• CR20NI80 — 1.12 Ohm*mm/m
• KHN70JU — 1.30 Ω*mm/m
• KHN20JUS — 1.02 Ohm*mm/m

The resistivity of nichrome fehrali indicates the main field of application: manufacture of devices of thermal action, household appliances and electric heating elements in industrial furnaces.

Because the nichrome and fehral mainly used in the manufacture of heating elements, the most common products — nichrome filament, tape, strip CR20NI80 and H15N60, and feralia wire KH23JU5T.