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Science

How is mains electricity produced?

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A voltage is produced when a magnet moves into a coil of wire. This principle is used in generators to produce electricity - either a coil of wire rotates in a magnetic field, or a magnet rotates in a coil of wire. Transformers are used to increase or decrease the voltage of alternating current (AC) supplies.

Making electricity

You should know how to produce an electric current using a coil of wire and a magnet.

Electromagnetic induction

A voltage is produced when a magnet is moved into a coil of wire. This process is called induction. The direction of the induced voltage is reversed when the magnet is moved out of the coil again. It can also be reversed if the other pole of the magnet is moved into the coil.

If the coil is part of a complete circuit then a current will be induced in the circuit.

Notice that no voltage is induced when the magnet is still, even if it is inside the coil.

Increasing the induced voltage

To increase the induced voltage:

  • move the magnet faster
  • use a stronger magnet
  • increase the number of turns on the coil
  • increase the area of the coil

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