Air Core Inductance – Lo (henry) 

The inductance that would be measured if the core had unity permeability and the flux distribution remained unaltered. 

Coercive Force – Hc (oersted or A/m) 

The magnetized field strength required to bring the magnetic flux density of the magnetized material to zero. 

Core Constant – C1 (cm-1

The summation of the magnetic path lengths of each section of a magnetic circuit divided by the corresponding magnetic area of the same section. 

Core Constant – C2 (cm-3)

The summation of the magnetic path lengths of each section of a magnetic circuit divided by the corresponding magnetic area of the same section. 

Curie Temperature – Tc (oC)

The transition temperature above which a ferrite loses its ferromagnetic properties. 

Disaccommodation – D

The proportional decrease of permeability after a disturbance of magnetic material, measured at constant temperature, over a given time interval. 

Disaccommodation Factor – DF

The disaccommodation factor is the disaccommodation after magnetic conditioning divided by the permeability of the first measurement times log10 of the ratio of time intervals. 

Effective Dimensions of a Magnetic Circuit – 

Area Ae (cm2), Path Length le (cm), and volume Ve (cm3

For a magnetic core of given geometry, the magnetic path length, the cross sectional area, and the volume that a hypothetical toroidal core of the same material properties should possess to be the magnetic equivalent to the given core. 

Field Strength – H (oersted or A/m)

The parameter characterizing the amplitude of the alternating field strength. 

Flux Density – B (gauss or mT)

The corresponding parameter for the induced magnetic field in an area perpendicular to the flux path. 

Flux Density, saturation – Bs (gauss or mT)

The maximum intrinsic induction possible in a material. 

Inductance Factor – AL (nH)

Inductance of a coil on a specified core divided by the square of the number of turns. Unless otherwise specified, the inductance test conditions for the inductance factor are at flux density < 10 gauss.

Loss Factor – tan δ / μ

The phase of displacement between the fundamental components of the flux density and the field strength divided by the initial permeability. 

Magnetic Constant – μo

The permeability of free space. µ0 = 4π × 10−7 H·cm

Magnetic Hysteresis – 

In the magnetic material, the magnetization charge present in the material causing an offset in the B-H loop as a result of this ‘memory’ effect.

Magnetically Soft Material – 

A magnetic material with low coercivity. A material which holds little or no residual magnetic charge.

Permeability, amplitude uΔ

The quotient of the peak value of the flux density and the peak value of the applied field strength at a stated amplitude of either, with no static present. 

Permeability, complex series – μs’, μs

The real and imaginary components respectively of the complex permeability expressed in series terms. 

Permeability, effective – μ

For a magnetic circuit constructed with an air gap or air gaps, the permeability of a hypothetical homogeneous material which would provide the same reluctance. 

Permeability, incremental – μΔ

Under stated conditions the permeability obtained from the ratio of the flux density and the applied field strength of an alternating field and a superimposed static field. 

Permeability, initial – μi

The permeability obtained from the ratio of the flux density, kept at < 10 gauss, and the required applied field strength. Material initially in a specified neutralized state. 

Power Loss Density – P (mW/cm3)

The power absorbed by a body of ferromagnetic material and dissipated as heat, when the body is subject to an alternating field which results in a measurable temperature rise. The total loss is divided by the volume of the body. 

Remanence – Br (gauss or mT) 

The flux density remaining in a magnetic material when the applied magnetic field strength is reduced to zero. 

Temperature Coefficient – TC

The relative change of the quantity considered, divided by the difference in the temperatures producing it. 

Temperature Factor – TF 

The fractional change in the initial permeability over temperature range, divided by the initial permeability.