Transformers

• A transformer consists of two coils wound on a common iron core
• 1. An alternating potential difference is applied across the primary coil
  2. causes current to flow/in alternating direction/
  3. A magnetic field around the coil will also alternate
  4. the magnetic field induces an alternating magnetic field in the iron core
  5. inducing a potential difference across the secondary coil
  6. Leading to current flow around secondary coil
• transformers transfer current between prinary coil to secondary coil using induced magnetic fields.
• Transformers - electricity can’t conduct straight across 


  Because wires are insulated in plastic so electricity doesn’t pass through iron core
• transformers only work with an alternating current because we need a changing magnetic field to induce potential difference not a constant magnetic field (direct current)
• Step up transformer


  Potential difference induced in secondary coil is double (greater)produced in primary coil as there are twice amount of turns in the secondary coil
• Step down transformer 


  Potential difference in secondary coil is half (less) than the primary coil because secondary has half the number of turns
• Step up transformer increase voltage to 400,000v to minimise energy loss / decrease current and reduce heat loss and then the voltage is decreased by a step down transformer to 230v so it’s safe to use in households
• Step up transformers increase voltage and decrease current
• Step down transformers decrease voltage and increase current