Page 474 - Basic Electrical Engineering
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as
A magnetic potential or magneto motive force (MMF) is expressed as the
product of the number turns of the coil and the current passing through it, i.e.,
MMF = N I (5.2)
Figure 5.3 Magnetic field around a current-carrying coil
The unit of I is Amperes, and number of turns has no unit. Thus, logically
the unit of MMF should be Amperes only. However, to differentiate the unit
of MMF from the unit of current, the unit of MMF is expressed as ampere
turns (AT).
The magnetic potential or MMF determines the magnetic flux around a
coil. To produce a particular amount of flux or flux density, the number of
turns or the current flowing, can be varied.
5.1.3 Magnetic Field Strength
