
Series

Parallel

Diagram



Current

same current through each resistor

current splits to flow through each resistor; total current through the whole circuit is the sum of the currents through the separate resistors

Potential difference

potential difference is split between the resistors  refer to potential divider rule.

potential difference across each resistor is the same

Resistance

resistance increases, current decreases, when resistors are combined in series

resistance decreases, current increases, when resistors are combined in parallel

Other properties

current has one path to flow through; if one resistor breaks, current stops flowing

current has more than one path to flow through; if one resistor breaks, current can still flow through other resistors

Formulae


For pairs this reduces to
ie. product over sum
For identical resistances in parallel, , ie. resistance value halves
