For the circuit in Fig. 3.24, find i_{1} to i_{4} using mesh analysis.
Note that meshes 1 and 2 form a supermesh since they have an independent current source in common. Also, meshes 2 and 3 form another supermesh because they have a dependent current source in common. The two supermeshes intersect and form a larger supermesh as shown. Applying KVL to the larger supermesh,
2i_{1} + 4i_{3} + 8(i_{3} – i_{4} ) + 6i_{2} = 0
or
i_{1} + 3i_{2} + 6i_{3} – 4i_{4} = 0 (3.7.1)
For the independent current source, we apply KCL to node P:
i_{2} = i_{1} + 5 (3.7.2)
For the dependent current source, we apply KCL to node Q:
i_{2} = i_{3} + 3 I_{o}
But I_{o} = -i_{4} , hance ,
i_{2} = i_{3} – 3i_{4} (3.7.3)
Applying KVL in mesh 4,
2i_{4} + 8(i_{4} – i_{3} ) + 10 = 0
or
5i_{4} – 4i_{3} = -5 (3.7.4)
From Eqs. (3.7.1) to (3.7.4),
i_{1} = -7.5 A , i_{2} = -2.5 A , i_{3} = 3.93 A , i_{4} = 2.143 A