Series vs. Parallel Circuits - Questions 7 Help

Wiring two or more devices together in a circuit can be done in a variety of ways. The two most common ways are to wire the devices in a series circuit or as a parallel circuit. Whether the devices are in a series or a parallel arrangement affects the properties that the circuit would exhibit.

Series Circuits are characterized by a single pathway from the + to the - terminal of the battery. The bulbs are arranged in a consecutive fashion such that any charge that passes through the first bulb will also have to pass through the second and the third bulb. Since each bulb offers resistance, arranging them in this consecutive order means that the resistance increases as additional bulbs are added. Three bulbs results in more resistance than two bulbs or one bulb. Adding more resistors increases the overall resistance and in turn decreases the flow rate or current in the circuit. This decreased flow rate is experienced by every bulb in the circuit.

Parallel circuits are quite different because the bulbs are all placed in an individual branch with each branch operating independently of the others. It is analogous to toll booths on a tollway. While each toll booth offers resistance to the flow of cars, placing each toll booth in its own lane (or branch) means that having more toll booth lanes will reduce the overall resistance and increase the flow of cars through the toll area. For circuits, it works similarly. Adding more bulbs will also add more branches (lanes) and decrease the overall resistance while increasing the flow rate or current in the battery. It is important to recognize that this increased flow rate is due to the additional lane for charge flow. The flow rate in the already existing branches is not affected by the addition of a new branch since the branches operate independent of each other.