Page 223 - Basic Electrical Engineering

Solution:

By examining the given network, we see that terminals P and Q are at the
same potential. The circuit is then redrawn as shown by connecting the 10 Ω

resistor between B and Q. Similarly a 5 Ω resistor is shown connected
between points A and P. The circuit is then simplified in steps as shown.

Figure 2.147

Equivalent resistance R AB = 3.75 + 6.67 = 10.42 Ω.

Now let us calculate the supply voltage so that P.D across AP is 25 V.

Assuming V = 25, from Fig. 2.147 (ii),
AP

Therefore V = V + V BQ
AP
= 25 V + 44.46 V

= 69.46 V