Magnetic force or magnetizing force is called magnetic field strength in physics. Magnetic materials such as steel are good paths for magnetic field lines. The path through which magnetic field lines pass is called magnetic circuit. In a magnetic circuit, the magnetic potential acting on a unit length is called magnetic field strength ( Or magnetizing force). The magnetic field strength is represented by the letter H, and its relationship with the magnetic potential is:

H=F/L

H-----Magnetic field strength, Ampere/cm;

F-----Magnetic potential, ampere;

L-----Magnetic circuit length, cm.

The magnetic potential is equal to the product of the current I through the coil and the number of turns W in the coil.