Figure 1.2 shows a magnetic circuit based on an electrical analogy. In general, a coil with N turns of wire and I amperes (amps) provides the magnetomotive force NI that pushes the magnetic flux <) through a region (or a material) with a cross sectional area a and a magnetic flux path length l. In the electrical analogy, a voltage V provides the electromotive force that pushes an electrical current Ithrough a region. The amount of magnetomotive force required per unit of magnetic flux is called reluctance 9L The amount of voltage required per amp is called resistance R.
FIGURE 1.2 Magnetic circuit with electrical analogy.
Electrical Analogy
Visualization of Flux Linkage
Figure 1.3
shows 10 magnetic flux lines passing
through 4 turns of wire in a coil. Each turn of the coil is linked to the 10 magnetic flux lines, like links in a chain. Therefore, the total flux linkage X is obtained by multiply-