Mains Electricity- P5 (OCR 21st Century)

The mains supply is AC, battery supply is DC.

In the UK the mains power supply is roughly 230 volts. It is produced by generators through a process called electromagnetic induction. It is an AC supply- which stands for alternating current- this means that the current is constantly changing its direction. Whereas batteries are a DC supply- which stands for direct current- this means the current is flowing in a constant direction. AC is used for the mains electricity as it is easily distributed and can be easily generated.

A voltage and possibly a current can be created within a conductor through moving a magnet in or near a coil of wire. This is referred to as electromagnetic Induction. As the magnet is moved near or in the coil of wire, the magnetic field of the coil changes. The change is the magnetic field causes a voltage, and a current flows within the wire- providing that it is a complete circuit. The voltage's directions depends on the movement of the magnet:

• If the magnet is moved into the coil the voltage is created in the opposite direction from when it is moved out of the coil.
• If the pole point of the magnet is reversed the voltage is induced in the opposite direction.
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AC Generators:

The purpose of generators is to generate electricity. A magnet rotates inside the generator in a coil of wire, as it turns the magnetic field within the coil changes. This causes a voltage to be created…