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Circuits

These are the circuit symbols.

You can wire the components in a circuit in two different ways, either in series or in parallel.

 

This is a circuit with two ​lamps connected in parallel                

This is a circuit with two lamps connected in series

- In a series circuit, if one of the lamps breaks, the flow of electricity is cut off and therefor the other lamp will not light.

- In a parallel circuit, if one of the lamps break, then the other will still light as it still has a flow of electricity running through it.

- The current is shared between each component connected in parallel. The total amount of current flowing into the junction, or split, is equal to the total current flowing out.​

- The current that flows through each component connected in series is the same.

- The sum of all the potential differences across the components in a series circuit is equal to the total potential difference across the power supply.

- In parralel, the sum of all the current in every branch is equal to the current from the electrical supply.

AC and DC current 

- AC electricity means alternating current, therefore the current is always changing direction. The mains electricity in the UK is about 230V and is an AC supply, it also has a frequency of 50Hz. This means that it changes its direction and back again 50 times every second. 

 

- DC electricity means direct current, therefore the current only flows in one direction. batteries are DC supply.