A potential divider is a simple circuit that uses resisters(or thermistors / LDR’s) to supply a variable potential difference.
They can be used as audio volume controls, to control the temperature in a freezer or monitor changes in light in a room.
Two resistors divide up the potential difference supplied to them from a cell. The proportion of the available p.d. that the two resistors get depends on there resistance values.
- Vin = p.d. supplied by the cell
- Vout = p.d. across the resistor of interest
- R1 = resistance of resistor of interest R1
- R2= resistance of resistor R2


Example; use the information in the diagram below to find Vout.

