Find the effective resistance between points A and B of the network shown if Fig.

$ 3 \Omega$

Resistors AF and FE of 3 $\Omega$ each are in series with each other.

 Therefore, the network AEF is a parallel combination of two 6 $\Omega$ resistors. Thus the resistance between points A and E is given by

          $R_{AE} = \frac{1}{6} + \frac{1}{6} = 3 \Omega$. The network reduces to that shown in Fig. (a). Similarly the resistances between points A and B is $3 \Omega$