This represents the time stability of permeability. The decrease in Permeability is approximately proportional to the log (Time).

Inductance is the ability of an inductor to induce emf when there is a change in current, It is also the flux linkage to unit current. The unit of inductance in Henry.

Inductance is the property of a conductor or a circuit, which resists the change in current. Hence, it causes current changes to drag behind voltage changes. An inductor stores the energy in the form magnetic field. Inductance is proportional to the square of number of turns and the proportionally constant is called inductance factor ( A_L) ie,

Magnetic loss is expressed as loss tangent (tan d) and the contribution comes from inductive (reactive, wL_s ) and resistive, R_s. tan d is the loss angle i.e., the angle between the Flux (B) and Applied field (H).

The loss angle is also directly related to the real (m') and imagenary (m") part of permeability, as represented by:

Loss factor is defined as the ratio of loss angle to initial
permeability. Which is inverse to the Q- factor.


Quality factor is the inverse of loss factor, tan d / mi. NiZn ferrites are capable of giving a higher Q factor at higher resistivity compared to MnZn ferrites. Q is sensitive to not only the chemical composition but the post sintered handling also. Proximity to strong magnetic field or mechanical stress can reduce the Q value of ferrites.


In a series inductive circuit, the reactive and resistive components are related to complex permeability by:

Where m" is the imaginary component and m.' is the real component. The graph below shows the behaviour of initial permeability (real and imaginery) at different frequencies.