MODULE 3

• Michael Faraday summed up conclusions of his experiments regarding electro-magnetic induction into two laws, known as Faraday's laws of electro-magnetic induction
• First Law


  Whenever a conductor cuts across the magnetic field, an emf is induced in the conductor
• First Law


  Whenever the magnetic flux linking with any circuit (or coil) changes, an emf is induced in the circuit
• Second Law


  The magnitude of induced emf in a coil is directly proportional to the rate of change of flux linkages
• When flux linking with a conductor (or coil) changes, an emf is induced in it
• This change in flux linkages can be obtained in the following two ways:
• Self-inductance


  The property of a coil due to which it opposes the change of current flowing through itself
• Mutual-inductance


  The property of one coil due to which it opposes the change of current in the other (neighboring) coil
• Series magnetic circuit


  A magnetic circuit that has a number of parts of different dimensions and materials carrying the same magnetic field
• Inductances in series (additive fields)


  Inductance of each coil is increased by M
• Inductances in series (subtractive fields)


  Inductance of each coil is decreased by M
• Inductances in parallel (same direction fields)


  Inductances add
• Inductances in parallel (opposite direction fields)

  Inductances subtract