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if considers analogous to electrical current, then the flux can be routed in a magnetic circuit just like an electrical current in an electrical circuit. As an example, bar magnet radiates flux from N and absorbed from S poles. If placed in air, it naturally does this, while some of the flux goes to infinity (not much understood, but calculations does proves). Analogous to wires in an electrical circuit, ferromagnetic material Magnetic Bar provides the "conductive" path for flux in a magnetic circuit. It is more common to use a "keeper" shortening two poles of horse shoe magnet, for storage. This is essentially a magnetic circuit, where all flux is channeled through the "keeper" into the magnet itself, blocking radiation or interaction with other magnetic material in the vicinity.

A typical transformer is an example to a magnetic circuit. Its core, usually with a square or ‘figure 8' cross section provides the necessary magnetic path for the flux to follow. This however does not confine all the magnetic flux to the core, so portion of the magnetic energy escapes to the environment. This essentially meaning magnetic interference to the neighboring devices and energy loss.

See below for toroidal core, which is a special type of an electromagnet, where all the flux contained within its core, eliminating magnetic interference and energy loss.

It is important to understand there are many difference between electrical and magnetic circuits, so it cannot be considered equal in its entirety.

Magnetic reluctance

This is analogous to electrical resistance in an electrical circuit. As electrons flows through the least resistance, magnetic flux tend to flow through the least reluctant path. Unlike resistance, Magnets don't dissipate energy in magnetic reluctance. Inverse of the Reluctance is called permeance, measured in Henry (same as inductance), but concepts are different.

Saturation

It is important to know that reluctance is non linier; meaning it varies depending on the magnetic field. When a high-permeable material is in the path of strong magnetic flux, it can be saturated, and reluctance goes high (limiting magnetic flux). This makes high permeable material becomes low permeable at the point of flux saturation. Above this level, reluctance increases rapidly. Reluctance also increases in low flux incidents.

Air, glass, water etc. are low permeable materials. Air gaps are used to reduce the saturation (increasing the saturation point), where more energy can be stored before the core get saturated. Meaning, more flux can be concentrated and channeled before reluctance increases.

Magnetic Assemblies

Ferromagnetic materials have a tendency to keep a memory of past MMF (magnetomotive force). Meaning, after the source of the magnetic flux is cut off; remnant magnetism is left in ferromagnetic circuits, creating a flux with no MMF.