Electromagnetic Induction

• Faraday
  • An electric current is induced in a conductor whenever the magnetic field in the region of the conductor changes.
  • moving wire in magnetic field
    • "cutting" magnetic field lines
  • moving magnet in a coil
  • Demo moving wire in magnetic field and moving magnet in coil
  • Faradays Iron Ring
    • only on change of current
  • factors affecting induced current
    • number of turns of coil
    • rate of change of magnetic field
    • magnetic field strength
  • induced potential
• Lenz (pronounced Lents) Law
  • For a current induced in a coil by a changing magnetic field, the electric current will be produced in such a direction that its own magnetic field opposes the change that produced it.
    • example coil
    • example wire in field
      • define motion direction of conductor in field
      • define force direction to oppose motion
      • use RH Rule to determine dir'n of electrical current
        • thumb - current
        • palm - force
        • fingers - magnetic field dir'n
• eddy current demo - cow magnet
• AC Generator or Alternator
  • Alternator
  • Generator