Series & Parallel Circuits (OCR GCSE Combined Science A (Gateway): Physics): Revision Note

Series & Parallel Circuits

• A series circuit consists of a string of two or more components, connected end to end:

Diagram showing two bulbs connected in series

• A parallel circuit consists of two or more components attached along separate branches of the circuit

Diagram showing two bulbs connected in parallel

Series Circuit

• A series circuit consists of a string of components connected in the same loop to a power supply

• In a series circuit:

  • The current is the same at all points around the loop

  • The potential difference of the power supply is shared between the individual components

• Two disadvantages of series circuits are:

  • If one of the components breaks, all of the others will stop working

  • The components cannot be controlled (switched on and off) separately

Construction of a simple series circuit with an ammeter, voltmeter, cell and resistor

Parallel Circuit

• The advantages of this kind of circuit are:

  • The components can be individually controlled, using their own switches

  • If one component stops working the others will continue to function

• In a parallel circuit, the current splits up - some of it going one way and the rest going the other

• This means that the current in each branch will be smaller than the current from the power supply