A magnetic circuit approximates a narrow core and its gaps by sections carrying a common magnetic flux . With negligible leakage and approximately uniform magnetic flux density across each section, Gauss's law for magnetism gives . The magnetostatic Ampère law then gives . This requires an appropriate material relation; constant magnetic permeability is an approximation for an actual magnetic core.
Magnetic fringing is the spreading of magnetic field lines near an air gap or pole edge, so the gap's effective magnetic flux area exceeds its geometrical pole-face area. A gap much shorter than its transverse dimensions permits a leading uniform-field approximation. High core magnetic permeability does not by itself justify neglecting magnetic fringing for a wide gap.
The magnetic reluctance of a linear section of magnetic circuit is the ratio of the winding's integrated magnetic field intensity to the magnetic flux, with units . For uniform length , cross-sectional area , and relative magnetic permeability , . Series sections carrying the same magnetic flux have additive magnetic reluctances, and .
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A magnetic circuit is a conceptual framework used to analyze the magnetic behavior of materials and devices, analogous to an electrical circuit. In a magnetic circuit, the flow of magnetic flux is compared to the flow of electric current in an electrical circuit. Here are the key components and concepts associated with magnetic circuits: 1. **Magnetic Flux (Φ)**: This is the measure of the quantity of magnetism, considering the strength and the extent of a magnetic field.