This 49-minute DVD provides a systematic means of reviewing the fundamental principles of electromagnetism and electromagnetic induction. It is intended as a general review of electromagnetic concepts to those with some background in basic electrical theory. It covers basic magnetism and electromagnetic theory. It also explains the characteristics of magnetic fields, the factors determining electromagnetic field strength, Lenz's Law, and principles used in electric motors, generators, and transformers.
Magnetism - 4 minutes
Defines the following terms: magnetic field, lines of force, magnetic flux, flux density. Demonstrates the direction of magnetic flux. Shows how the direction of flux can be determined. Lists four characteristics of magnetic fields.
Electromagnetism - 9 minutes
Defines the term electromagnetic field. States the circumstances under which two magnetic fields tend to reinforce each other. States the circumstances under which two electromagnetic fields tend to cancel each other out. Demonstrates the left-hand rule for current-carrying conductors. Demonstrates the left-hand rule for coils.
Field Strength - 10 minutes
Defines the following terms: magnetomotive force, field intensity, permeability, saturation. Lists three factors affecting the field strength of a coil. Explains how core saturation limits the field strength of a coil.
Motor Action - 9 minutes
Defines motor action. Demonstrates the right-hand motor rule. Explains how the right-hand motor rule applies to the rotary motion of an electric motor.
Generatorsm - 9 minutes
Lists the requirements for electromagnetic induction. Lists the factors affecting the magnitude of an induced EMF. Lists the factors affecting the polarity of an induced EMF. Demonstrates the left-hand generator rule.
Transformers - 8 minutes
Explains how a transformer meets the three requirements for electromagnetic induction. Explains how a permeable core helps increase transformer efficiency. Defines the terms magnetic coupling and magnetic circuit. States Lenz's Law and explains how it applies to a transformer