Alternator and Dynamo (T)

• What is the purpose of the video?

  To describe how an alternator generates an alternating current and how a dynamo generates a direct current.
• What is the generator effect?

  • A conducting wire passing through a magnetic field induces a potential difference.
  • If the wire forms a complete circuit, a current is induced.
• How does an alternator generate an alternating current?

  By rotating a coil of wire in a magnetic field, inducing an alternating potential difference.
• What are the components of an alternator?

  A coil of wire and two metal rings called commutators.
• What happens to the potential difference when the coil is horizontal?

  The potential difference is at its maximum.
• Why does the potential difference fall to zero when the coil is vertical?

  Because the coil is moving parallel to the magnetic field.
• What is the relationship between the strength of the magnetic field and the size of the alternating current?

  • Increasing the strength of the magnetic field increases the size of the alternating current.
  • Increasing the number of turns on the coil also increases the current.
  • Increasing the area of the coil increases the current.
  • Increasing the rotation speed of the coil increases both the size and frequency of the current.
• What type of current does a dynamo produce?

  A direct current (DC).
• What is a key feature of a dynamo?

  It has a split ring commutator.
• How does the split ring commutator affect the current in a dynamo?

  It prevents the direction of the current from reversing.
• How many peaks are observed in the potential difference graph for each full rotation of the coil in a dynamo?

  Two peaks for each full rotation.
• What happens to the potential difference when the coil in a dynamo is vertical?

  • The potential difference falls to zero.
  • This occurs because the coil is moving parallel to the magnetic field.