How transformers work

• Do transformers work with alternating or direct electrical supplies

  Transformers only work with alternating electrical supplies
• What do transformers do

  Change the voltage and current of an alternating current
• What does a step-down transformer do

  Decreases the voltage and increases the current
• Where could a step-down transformer be used

  Could be used before electricity enters a home, to ensure the voltage is low enough to be safe
• What does a step-up transformer do

  Increases the voltage and decreases the current
• Where could a step-up transformer be used

  Could be used as electricity leaves a power station and enters the national grid
• Why is it important to use step-up transformers before electricity is transmitted across the national grid

  It’s important to have a very high voltage and low current to minimise energy loss during transmission
• How do transformers work

  When supplied with an alternating current the primary coil will generate an alternating magnetic field

  This then induces an alternating magnetic field in the iron core

  This, in turn, induces an alternating voltage in the secondary coil, which - if the circuit is complete - will lead to an alternating current