Voltage in Series & Parallel (Edexcel IGCSE Physics (Modular))

Voltage in series & parallel

Voltage in series

• In a series circuit, the total voltage of a power supply is shared between the components

Lamps connected in a series circuit share the potential difference from the battery

• For two identical components (with equal resistance), the voltage across them will be:

  • the same

  • equal to half the total voltage of the power supply

• For two non-identical components (with different values of resistance), the voltage will be:

  • higher across the component with the higher resistance

  • lower across the component with lower resistance

Voltage in parallel

• In a parallel circuit, the total voltage across each branch is the same as the voltage of the power supply

Lamps connected in a parallel circuit all have the same voltage across them

Advantages & disadvantages

Advantages and disadvantages of a series circuit

• A series circuit consists of a string of two or more components connected in a loop

In a series circuit, only one switch is needed to control all of the lamps. This can be seen as an advantage or as a disadvantage

Advantages of a series circuit

• All of the components are controlled by a single switch

• Fewer wires are required

Disadvantages of a series circuit

• The components cannot be controlled separately

• If one component breaks, all other components stop working

Advantages and disadvantages of parallel circuits

• A parallel circuit consists of two or more components attached across different branches of the circuit

In a parallel circuit, the lamps are connected in parallel and can be switched on and off by their own switches

Advantages of a parallel circuit

• The components can be individually controlled using their own switches

• If one component breaks, then the others will continue to function

Disadvantages of a parallel circuit

• Many more wires are involved which can be more complicated to set up

• All branches have the same voltage as the supply making it more difficult to control the voltage across individual components