Page 159 - Basic Electrical Engineering

Figure 2.55

Solution:

First we remove the load resistance R from the circuit and calculate the open
L
circuit voltage, V OC across its terminals A and B as,

Figure 2.56

Let current I be known through the loop as shown.

voltage drop across PQ is equal to IR = 2 × 8 = 16 V. Terminal P is at higher
potential than terminal Q. No current is flowing through the 3 Ω and 5 Ω
resistors in the circuit because these are open circuited. The potential of A

with respect to B is calculated starting from point B as

V AB = V BQ + V + V − V SA
QP
PS
= 0 + 16 V + 0 − 12 V