• When two resistors are connected in series, through?Kirchhoff’s Second Law, the potential difference across the power source is divided between them
• Potential dividers are circuits that can produce an output voltage as a?fraction?of its input voltage
• The main purposes of a potential divider are:
  • To provide a?variable?potential difference
  • To enable a?specific?potential difference to be chosen
  • To?split?the potential difference of a power source between two or more components

• Potential dividers have a wide range of applications in devices requiring features such as volume control and sensory circuits
  • This can be achieved using components such as LDRs and thermistors
• Potential divider circuits are based on the?ratio?of voltage between components
• This is equal to the ratio of the resistances of the resistors in the diagram below, giving the following equation:

Potential divider diagram and equation

• The input voltage Vin?is applied to the top and bottom of the series resistors
• The output voltage Vout?is measured from the centre to the bottom of resistor R2
• The potential difference?V?across each resistor depends upon its resistance?R:
  • The resistor with the?largest resistance?will have a?greater potential difference?than the other one from?V?=?IR
  • If the resistance of one of the resistors is increased, it will get a greater share of the potential difference, whilst the other resistor will get a smaller share
• In potential divider circuits, the p.d across a component is proportional to its resistance from?V?=?IR