the generator effect

• alternating current:

  • coil cuts magnetic field lines
  • so, potential different is induced across coil
  • there is a complete circuit, so current induced in coil
  • every half turn, potential difference reverses directions
  • so, every, half turn, current changes direction
• direct current:

  • coil cuts magnetic field lines
  • so, potential difference induced across coil
  • there is complete circuit, so, current induced in coil
  • wires not attached to split ring
  • each split ring has positive and negative change that is constant
  • so, current flows in one direction
• • alternators induce alternating current
  • they have slip rings and brushes
  • slip rings provide continuous connection between coil and brushes
• • dynamos induce direct current
  • they have split ring commutators
  • split ring commutators swap connection of brushes every half turn
• • disconnecting the alternator from the lamp makes the handle easier to turn
  • there is no induced current
  • so, there is no magnetic field around coil
  • so, no force can oppose movement of coil
• • a microphone converts pressure variations in sound waves into variations in current
• microphone:

  • sound waves causes diagraphm to vibrate
  • so, diagraphm causes coil to vibrate
  • so, current generated
  • so, current produces magnetic field around coil
  • so, coil cuts magnetic field lines
  • so, potential field induced across ends of coil