Electrical Conductance
Electricity and Magnetism

Conductance, electrical

Glossary Definition for 16-19 IOP Glossary Project


The electrical conductance of a component in an electric circuit is a property of a component that describes how the electric current in the component is related to the electrical potential difference (voltage) across it. The greater the electrical conductance, the larger the current for a given potential difference, and the smaller the potential difference, for a given current.

Electrical conductance is usually represented by the symbol G.

Electrical conductance is defined, for some component, by the equation

G = IV

where V is the electrical potential difference across the component and I the corresponding electric current.


Conductance is simply the reciprocal of resistance.

SI unit

siemens, S

Expressed in base units

kg-1 m-2 s3 A2

Other commonly used unit(s)

mho (1 mho = 1 Ω-1 = 1 S)

Mathematical expressions

Conductance is related simply to resistance as

G = 1R

The conductance of a component is related to the electrical conductivity, σ, of the material from which the component is made, by

G = σ AL

where A is the component’s cross-sectional area and L is its length.

Electrical Conductance
appears in the relation G=1/R G=σA/L
2023 IOP Awards

Teachers of Physics Awards

Recognising and celebrating outstanding contributions to the field of physics education.

Learn more