How is a magnetic circuit similar to an electric circuit?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

electromagnet Figure 1: Elements of a solenoid

A magnetic circuit is analogous to an electric circuit because both systems follow a mathematical relationship similar to Ohm’s law. While nothing actually flows in a magnetic circuit—unlike the flow of electric charge in an electric circuit—the following components are directly comparable:1

Magnetic Flux ( $Φ$ ): Analogous to electric current. It represents the total lines of a magnetic field confined to a closed path.1
Magnetomotive force (mmf or $f$ ): Analogous to electromotive force (voltage). It is the factor that establishes the flux and is measured in ampere-turns.1
Reluctance ( $r$ ): Analogous to resistance. It represents the opposition to the presence of magnetic flux, determined by the material's permeability and the geometry of the circuit.1

In summary, the relationship is expressed as $Φ = f / r$ , where magnetic flux is equal to the magnetomotive force divided by the reluctance.1