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  • Created by: Jasmin
  • Created on: 16-05-13 12:56
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  • Transformers
    • Used to change the size of alternating pd
    • Step up transformers
      • Step voltage up
      • More turns on secondary coil than primary
      • Greater pd on secondary than primary
    • Step down transformers
      • Steps voltage down
      • More turns on primary coil than secondary
      • Secondary less pd than primary
    • Electromagnetic induction
      • Primary coil produces mf which stays within iron core - nearly all passed to secondary hardly any lost
      • AC in primary coil - connected to AC supply
      • Field constantly changing direction, felt by secondary
      • Changing field induces alternating pd across secondary
      • Number of turns determines whether pd induced in secondary is greater or less than pd in primary
      • Only AC not DC (no change in field - secondary pd = 0)
    • Iron core
      • Transfers changing mf from primary to secondary
      • No current flows through
      • Core is laminated to cut out induced currents in iron layers
      • If not laminated efficiency reduced


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