Transformers

• Transformers change the potential difference of an alternating current
• Step up transformer

  • More coils on secondary coil than primary coil

  1. When an alternating potential difference is applied across the primary coil, it produces an alternating magnetic field
  2. As iron is also magnetic, the core becomes magnetised
  3. This changing magnetic field induces a potential difference in the secondary coil
• Step down transformer

  • More coils on primary coil than secondary coil

  1. When an alternating potential difference is applied across the primary coil, it produces an alternating magnetic field
  2. As iron is also magnetic, the core becomes magnetised
  3. This changing magnetic field induces a potential difference in the secondary coil
• Pd across primary / pd across secondary = number of turns of primary / number of turns on secondary

  Vp / Vs = Np / Ns