How Transformers Work

• What is the primary function of transformers in the national grid?

  To increase or decrease voltage
• Why is electricity generated at huge power stations spread out across the UK?

  To ensure widespread electricity distribution
• What happens to electricity after it is generated in power stations?

  It passes through step up transformers
• What voltage does a step up transformer increase electricity to?

  Around 400,000 volts
• What is the purpose of increasing voltage in the national grid?

  To minimize energy losses during transmission
• What happens to electricity when it reaches a small town?

  It passes through a step down transformer
• What voltage does a step down transformer decrease electricity to?

  Around 230 volts
• What is the role of a transformer?

  To increase or decrease voltage
• What is the iron core in a transformer used for?

  To connect the primary and secondary coils
• What happens when an alternating potential difference is applied to the primary coil?

  A current flows and generates a magnetic field
• How does the magnetic field in the primary coil affect the iron core?

  It induces an alternating magnetic field in the core
• What does the iron core's magnetic field induce in the secondary coil?

  A potential difference across the secondary coil
• Why can't electricity pass directly from the primary to the secondary coil?

  Because the wires are insulated in plastic
• If a step up transformer has twice as many turns in the secondary coil, what happens to the voltage?

  The voltage gets doubled
• What is the effect of a step down transformer on voltage?

  It decreases the voltage
• What are the steps involved in how a transformer works?

  1. Alternating potential difference applied to primary coil
  2. Current flows, generating a magnetic field
  3. Alternating magnetic field induces magnetic field in iron core
  4. Iron core's magnetic field induces potential difference in secondary coil
  5. Current flows in the secondary coil
• What are the differences between step up and step down transformers?

  • Step up transformer:
  • Increases voltage
  • More turns in secondary coil
  • Step down transformer:
  • Decreases voltage
  • Fewer turns in secondary coil