Lamps connected in series. Circuit diagram showing two lamps connected in series. The components are represented by standard symbols. At upper left is a battery consisting of two cells; an open switch is at upper right; and the lamps are at bottom. When the switch is closed, the potential difference (voltage) of the battery will cause electric current to flow round the circuit and the lamps will light up. The arrangement of the circuit affects the brightness of the lamps. When they are connected in series (as here), the battery is working against a greater resistance than when the lamps are connected in parallel, and the battery drives a smaller amount of current through the lamps. When connected in parallel to the same battery, the lamps will be brighter. See T356/600 for an example of lamps connected in parallel.