Lamps connected in parallel. Animation showing a simple circuit (one lamp) and two lamps connected on parallel. The potential difference (voltage) of the battery (left) causes an electric current to flow round the circuit, which lights the lamps. The arrangement of the circuit affects the brightness of the lamps. When they are connected in parallel (as here), the battery can drive a larger amount of current through the lamps than if the lamps were connected in series. When connected in series to the same battery, the lamps will be dimmer.