Iron Core Inductor
The inductance value on the air core inductor depends on the number of spires (turns), length, diameter, thickness of the spiral, etc. The air core inductance range of values is limited. In order to increase the inductance value of an inductor, an iron core is placed inside it, so an iron core inductor is used.
This iron core has very special magnetic characteristics. What they do is to reinforce the magnetic field. The magnetism of the core material depends on the bias of “the molecular magnetic domains”, when the magnetic field that affects the inductor changes continuously.
These domains should be able to change its position so that the core meets its goal. The magnetic domains may or may not follow the magnetic field variations, depending on the material the core is made of.
If the magnetic field variation can not be followed, the core is useless and the molecular domains get disordered, leaving the core magnetically unbiased.
Types of inductor’s core depending on frequency
The magnetic material that is used as the inductor core depends on the frequency at which it will work.
- Solid Iron Core: for very low frequencies.
- Laminated Iron Core: for frequencies from 10 hertz (Hz) to some kilohertz (kHz)
- Iron powder Core: for frequencies over hundreds of kilohertz and up to several hundreds of megahertz (MHz)
- Air Core: frequencies higher than 500 Megahertz. In this case, the iron core becomes obsolete.
Note: 1 hertz = 1 cycle per second