Chap 17: EMI Flashcards
Magnetic flux
Product of an area and the component of the magnetic flux density perpendicular to that area.
Example: The magnetic flux through a surface is given by the equation Φ = B⋅A, where B is the magnetic flux density and A is the area of the surface.
Magnetic flux linkage in a coil
Product of the magnetic flux passing through the coil and the number of turns of the coil.
Example: The magnetic flux linkage in a coil with 100 turns and a flux of 0.5 Wb is 50 Wb-turns.
Faraday’s law of electromagnetic induction
The magnitude of the induced e.m.f in a conductor is directly proportional to the rate of change of magnetic flux linkage (or the rate of cutting of flux).
Example: According to Faraday’s law, if the magnetic flux through a coil changes at a rate of 2 Wb/s, the induced e.m.f in the coil will be 2 V.
Lenz’s law
The direction of the induced e.m.f is such that it produces effects that oppose the change that causes it.
Example: Lenz’s law states that if the magnetic flux through a coil decreases, the induced e.m.f will produce a current that creates a magnetic field to oppose the decrease in flux.
