We define the magnetic field as a region around a magnetic material or a moving electric charge within which the force of magnetism acts.
The following are the three sources of magnetic fields:
- Current-carrying conductors
An electric current produces a magnetic field. This magnetic field can be visualized as a pattern of circular field lines circling a wire.
- Permanent magnets
Permanent magnets are the most common sources of the magnetic field. Nevertheless, the magnetic fields of permanent magnets are hard to calculate and need an understanding of intricate ferromagnetic phenomena. A compass needle is an example of a permanent magnet.
A simple electromagnet comprises a coil of wire wound around an iron core. The iron core assists to increase the magnetic field created. The strength of the magnetic field generated is proportional to the amount of current through the winding.
Watch the video below to understand the occurence of magnetic field and its illustration.