Revise GCSE Physics


Question:What types of electricity are there?

AC and DC.

Which stands for Alternating Current electricity and Direct Current electricity.


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In Direct Current electricity the electric charges flow in one direction.

The voltage from the power supply or battery (or cell) makes the current flow.

The value of the voltage determines what the current does.

So in DC electricity the voltage must have a constant value.


In Alternating Current electricity the electric charges move backwards and forwards.

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In alternating current, the electric current follows the direction of the voltage again, so the voltage must be changing direction constantly in order for the current to also change direction. The chart shows what the alternating voltage would look like.

For British mains supply electricity the frequency of the Alternating Current is 50Hertz.

This means that the electricity moves backwards and forwards 50 times every second.