## COPPER

## Copper Magnet Wire

Since the beginning of the electrical age, copper has been recognized for its unique and beneficial qualities in electrical applications. Copper is a malleable and ductile material with excellent conductivity. Elektrisola's electrolytic copper (Cu-ETP) is of high purity. We use copper (99.95%) which enables us to produce ultrafine wire down to a diameter of 10 microns. Copper magnet wire is available in diameters from 0.010mm to 0.500mm (AWG 58 - 24) with all insulation and self-bonding enamel types. Besides enamelled copper wire, Elektrisola also produces copper bare wire from 0.010mm to 0.20mm (AWG 58 - 32).

## Features

- High conductivity
- Good solderability
- High ductility

## Applications

- Industrial electronics
- Automotive
- Appliance
- Audio and Video
- Watches
- Computers

## Typical values

Cu | ||

Tensile strength | [N/mm²] | 220-300 |

Yield strength at 1% elongation | [N/mm²] | 120-200 |

Conductivity | [S*m/mm²] | 58.5 |

Resistivity | [Ohm*mm²/m] | 0.0171 |

Thermal coefficient of resistance | [1E-6/K] | 3900-4300 |

Density | [kg/dm³] | 8.9 |

## Resistance Calculations

### Resistance of a conductor (e.g. copper wire)

The resistance *R* of a copper wire with the length *l* can be calculated with the following formula:

where*R* is the resistance of the conductor in Ohms*l* is the length of the conductor in meters*ρ* is the electrical resistivity (also known as the specific electrical resistance) of a conductor. *A* is the cross-sectional area, measured in square millimeters*π* is the mathematical constant*d* is the nominal diameter of the wire in millimeters

### Resistivity ρ

Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a wire opposes electric current. A low resistivity indicates a wire that readily allows the movement of electrical charge. Copper has a resistivity of 0.0171 Ohm · mm²/m and is, therefore, one of the best conductors for electric current (slightly behind pure silver).

### Conductivity γ

Electrical conductivity or specific conductivity is a measure of a material's ability to conduct an electric current. It is the reciprocal (inverse) of the electrical resistivity. Annealed copper wire has a minimum conductivity of 58 S*m/mm², which is equivalent to 100% IACS (International Annealed Copper Standard), actual values typically reach 58,5-59 S*m/mm²

### Thermal coefficient of electrical resistance

The electrical resistance is depending on the temperature the wire is exposured to. This relationship between resistance and temperature is expressed by the thermal coefficient of resistance *α*. To calculate the resistance of a coil or wire at the temperature *T* you can use the following formula:

where*α* is the thermal coefficient of resistance*R*_{T} is the resistance of the coil at the temperature T*R*_{20} is the resistance of the coil at 20°C