Objectives

After studying this chapter, you will be

able to answer these questions:

1. How are electrical components con-

nected in parallel?

2. What are the laws of parallel circuits?

Important

Words and Terms

The following words and terms are key

concepts in this chapter. Look for them as

you read this chapter.

conductance (G)

equivalent resistance

parallel

parallel circuit

siemens (S)

When we were studying the series cir-

cuit, the example of the highway between

two towns was used. We learned that the

several bridges along that highway were in

series and each bridge offered a definite

amount of resistance to the flow of traffic. As

more automobiles are used each day, the

need exists to provide better and faster

highways. Your state may be constructing

new or widened highways so more cars may

travel safely without the resistance of narrow

bridges and curves. The reason is apparent;

more cars can travel on a new two- or three-

lane roadway than could travel on the old

one-lane road. In fact, twice as many cars can

travel on a double road, three times as many

on a three-lane road and so on.

If road A has the capacity of ten cars

per minute and road B has a capacity of

ten cars per minute, then roads A and B

together have a capacity of 20 cars per

minute, Figure 7-1. The bridges on each

55

Bridges

10 cars/min.

10 cars/min.

Road B

Road A

Figure 7-1.

The bridges are in parallel.

7

Parallel

Circuits