Resistance of a conductor (MA001E)

The resistance of an homogeneous conductor depends on the length, cross-sectional area and the nature of the material. The next formula is used to calculate the resistance from those quantities: 

 

Fórmula 1

R = ρ x L/S

Where:

R = conductor´s resistance in Ω (Ω)

ρ = resistivity or specific resistance of the used material

L = length in meters (m)

S = cross sectional area in square millimeters (mm²)

Derivated Formulas:

Formula 2

L = R x S/ ρ

Formula 3

S = ρ x L/R

Application Example:

What is the resistance of a length of homogenous copper wire with a Constant cross sectionnal area of 0,5 mm²?

Data:

L = 1 m

ρ = 0,016

S = 0,5 mm²

R = ?

Applying formula 2.1:

R = 0,016 x 1 / 0,5 = 0,032 Ω