Question
What is the net resistance between points A and F in the circuit shown in fig.(a)?

Fig. (a)

Fig. (b)

Fig. (c)

Fig. (d)
Solution
Firstly, considering the parallel combination BC.
The resistance of this combination is given by
Substitute 10 Ω for the combination and redraw the circuit as shown in fig.(b).
Now, the series combination BD can be replaced by a single resistor of resistance
R = 10 + 2 = 12 Ω
Now the circuit can be redrawn as in fig. (c).
Combination AE in the parallel arrangement can be replaced by a single resistor of resistance given by
The circuit can again redrawn as shown in fig.(d).
The resistance between points A and F (series) is given by
R = 10 + 7 = 17 Ω.
The resistance of this combination is given by
Substitute 10 Ω for the combination and redraw the circuit as shown in fig.(b).
Now, the series combination BD can be replaced by a single resistor of resistance
R = 10 + 2 = 12 Ω
Now the circuit can be redrawn as in fig. (c).
Combination AE in the parallel arrangement can be replaced by a single resistor of resistance given by
The circuit can again redrawn as shown in fig.(d).
The resistance between points A and F (series) is given by
R = 10 + 7 = 17 Ω.