Use of Transformers (AQA GCSE Physics)

• The type of current produced in power stations is alternating current (AC) which is transferred to homes via the National Grid
• Transformers are used to increase and decreases the potential difference of the current before and after transmission across the National Grid
• They are made up of two coils of wire, called the primary and secondary coils, around a magnetic iron core
  • A step-up transformer has more turns on the secondary coil than the primary
  • A step-down transformer has more turns on the primary coil than the secondary

A step-up transformer

• Step-up transformers are used to increase the potential difference from the power station to the transmission cables
• Step-down transformers are used to decrease the potential difference, to a much lower value, from transmission cables for domestic use (houses, offices, shops)