What does the hysteresis loop represent?

Hysteresis loop is a four-quadrant $$ B-H $$ graph from where the hysteresis loss, coercive force, and retentively of $$ s $$ magnetic material are obtained.

To understand hysteresis loop, we suppose to take a magnetic material to use as a core around which insulated wire is wound. The coils are connected to the supply $$ (DC) $$ through the variable resistor to vary the current $$ l $$. We know that current $$ l $$ is directly proportional to the value of magnetizing force $$ (H) $$ as Where $$ N= $$ no.of the turn of the coil, and $$ l $$ is the effective length of the coil. The magnetic flux density of this core is $$ B $$ which is directly proportional to magnetizing force $$ H $$.

Now, we should be familiar with some important terms related to hysteresis Loop.

From the hysteresis loop, a number of primary magnetic properties of a material can be determined.

1. Retentivity: A measure of the residual flux density corresponding to the saturation induction of a magnetic material. In other words, it is a material's ability to retain a certain amount of residual magnetic field when the magnetizing force is removed after achieving saturation. (The value of $$ B $$ at point $$ b $$ on the hysteresis curve.)

2.Residual Magnetism or Residual Flux- the magnetic flux density that remains in a material when the magnetizing force is zero. Note that residual magnetism and retentivity are the same when the material has been magnetized to the saturation point. However, the level of residual magnetism may be lower than the retentivity value when the magnetizing force did not reach the saturation level.

3.Coercive Force- The amount of revers magnetic field which must be applied to a magnetic material to make the magnetic flux return to zero.(The value of Hat point $$ c $$ on the hysteresis curve.)

4.Permeability- A property of a material that describes the ease with which a magnetic flux is established in the component.

5.Reluctance- Is the opposition that a ferromagnetic material shows to the establishment of a magnetic field. Reluctance is analogous to the resistance in an electric circuit.