Given:

Es = 30 volts

IT = 15 amps

The equivalent resistance of the circuit shown in figure 50 on the previous

page is smaller than either of the two resistors (R1, R2).

A point to

remember is that the equivalent resistance of a parallel circuit is always

less than the resistance of any branch.

Equivalent resistance can be found if you know the individual resistance

values and the source voltage. By calculating each branch current, adding

the branch currents to calculate total current, and dividing the source

voltage by the total current, the total can be found. This method, while

effective, is somewhat lengthy.

A quicker method of finding equivalent

resistance is to use the general formula for resistors in parallel:

If you apply the general formula to the circuit shown in figure 50, you will

get the same value for equivalent resistance (2 Ohms) as was obtained in the

previous calculation that used source voltage and total current.

Given:

R1 = 3 Ohms

R2 = 6 Ohms

Integrated Publishing, Inc. |