• Created by: JTre
  • Created on: 16-03-19 18:32
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  • Transformers + national grid
    • Mains electricity
      • mains electricity is an ac supply
        • ac means alternating current
          • repeatedly reverses its direction
          • to find the frequency of an ac supply, measure the time period of the waves.
            • frequency = 1/time taken for one cycle
      • frequency of 50Hz
      • has a live wire and neutral wire
        • live wires are alternatively positive and negative every cycle
        • neutral wires are 0 volts
    • National grid
      • the national grid supplies electricity across the country
      • connects power stations to homes, workplaces and public buildings.
      • the electricity is produced either by generator, nuclear, solar or some other source
    • transformers
      • the number of coils determines whether the transformer will step up or step down
      • a transformer is a device that increases, or decreases, the potential difference of an a.c current
      • they can only work with ac current
      • a basic transformer is made from two coils of wire
        • a primary coil from the ac current input  and a second leading to the ac output
          • they are not electrically connected
        • wound around an iron core which carries magnetic fields from one coil to the next


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