Conductance vs. Inductance — What's the Difference?

Conductance is the reciprocal of electrical resistance and describes how well a conductor allows the passage of electric current. It is especially important in discussions about the efficiency of electrical circuits, as higher conductance implies lower resistance and hence easier flow of electricity. In contrast, inductance is a property of electrical conductors that causes them to oppose changes in electric current passing through them. This quality is particularly significant in alternating current (AC) circuits and in the designing of transformers and inductors.

The unit of conductance, the siemens, signifies a component's ability to conduct electric current. Higher conductance means a material or component offers less opposition to current flow. Conversely, the unit of inductance, the henry, represents the extent to which a component such as a coil can store magnetic energy, essentially resisting changes in current that flows through it.

Conductance is primarily influenced by the material’s properties such as its conductivity, dimensions, and temperature. Metals with high conductivity, like copper and silver, typically exhibit high conductance. Meanwhile, inductance depends on factors like the number of turns in the coil, the coil's area, the type of core material, and how the coil is wound. More turns or a ferromagnetic core increases a coil’s inductance.

In practical applications, conductance is crucial for determining how efficiently electrical devices operate, influencing everything from electrical wiring to high-precision resistors. Inductance is key in the function of transformers, motors, and generators, where it is used to convert energy from one form to another efficiently.

While conductance focuses on the ease of current flow within a conductor, inductance involves the interaction between currents and magnetic fields within circuits, emphasizing how current changes influence voltages and vice versa.