Since the current obtained in the above calculations is a positive 2 amps,

the assumed direction of the current was correct. To show what happens if

the incorrect direction of current is assumed, the problem will be solved as

before, but with the opposite direction of current.

The circuit redrawn

showing the new direction of current and the new polarities is in figure 30.

Starting at point A, the loop equation is:

E3 + EA + E1 + E2 = 0

(I x R3) + EA + (I x R1) + (I x R2) = 0

FIGURE 30.

INCORRECT DIRECTION OF ASSUMED CURRENT.

Substituting values:

(I x 15 Ohms) + 60 volts + (I x 5 Ohms) + (I x 10 Ohms) = 0

Combining like terms:

(I x 30 Ohms) + 60 volts = 0

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