Topic 13

• A device that makes use of the generator effect to generate alternating current.

  Alternator
• A device that makes use of the generator effect to generate direct current.

  Dynamo
• When there is relative motion between an electrical conductor and a magnetic field, a potential difference will be induced across the ends of the of the conductor. A current will flow if this conductor is part of a complete circuit.

  Generator Effect
• A device that converts variations in current into vibrations of a diaphragm to produce corresponding sound waves.

  Loudspeaker
• A device that converts the pressure variations in sound into corresponding current variations.

  Microphone
• Metal wires that are part of the National Grid. Electricity is transported along them at very high voltages to reduce the energy loss and make the transportation more efficient.

  Power Cables
• A transformer that has a smaller potential difference in the secondary coil than in the primary coil. This is a result of the secondary coil having fewer turns.

  Step-Down Transformer
• A transformer that has a larger potential difference in the secondary coil than in the primary coil. This is a result of the secondary coil have more turns.

  Step-Up Transformer
• An iron core with a primary and secondary coil of wire wound around opposite ends, they can change the magnitude of an alternating voltage.

  Transformers
• The number of turns in the primary coil of a transformer over the number of turns in the secondary coil. This is equal to the voltage ratio for a 100% efficient transformer.

  Turns Ratio
• The potential difference across the primary coil of a transformer over the potential difference across the secondary coil.

  Voltage Ratio