| EMI (Electromagnetic Interference) | 
| A useful definition of EMI noise is any signigicant signal energy that causes unintended, undesirable circuit function or inadequate EMC performance. | 
|  | 
| AC Initial Permeability (£giac) | 
| This is the limit value of magnetic core permeability at the origin of the virgin magnetization curve. It’s given by the following formula: | 
|  | 
|  | 
| Inductance (L): | 
| The magnetic flux linkages in Maxwells-turns per ampere of magnetizing current. | 
|   | 
|  | 
| Inductance Factor (AL) | 
| Inductance factor is defined as the self inductance per unit turn of a coil of a given shape and dimension wound on a magnetic core, and is determined by the following formula: | 
|  | 
|  | 
| Quality Factor (Q): | 
| The efficiency of an inductor, that is the ratio of series inductive reactance to loss resistance. | 
|  | 
|  | 
| Loss factor (tan£_): | 
| Deviation from ideal phase angle (90°) due to losses. | 
|  | 
|  | 
|  | 
| Relative Loss Factor (tan£_ /£giac) | 
| Losses per unit of permeability. Figure merit of a material. | 
|  | 
|  | 
| Curie Temperature (Tc): | 
| emperature at which a ferromagnetic material loses its ferromagnetism and becomes paramagnetic(£g approaches 1) | 
|  | 
|  | 
| Relative Temperature Coefficient of lnitial permeability (£\£gr): | 
| This is the value obtained by dividing the temperature coefficient of the initial permeability(£\£g) by the initial permeability. | 
|  | 
|  | 
| Specific Gravity (d) | 
| It’s calculated from its volume and weight, as shown below: | 
|  |