Electricity
Energy Transfer
Appliances that need a lot of power use mains electricity.
Electricity is transferred to our homes via the National Grid.
Energy is transferred in different ways in different appliances
Direct current
Cells and batteries have a positive and negative terminal.
The direction of the charge stays the same, this is called Direct Current (D.C.)
The voltage does not change over time and shows as a flat line on a graph.
Alternating current
Mains electricity is produced using generators that rotate. This means that the direction constantly changes. This is called Alternating Current (A.C.)
The voltage changes and therefore the graph goes up and down. and appears as a wave
In the UK, the mains is supplied at 50Hz and an average voltage of 230v (220-240v)
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