Problem 4-27

Write a complete set of mesh equations for the circuit.

Note to grader: I asked them to write the equations only, they did not have to simplify or solve them.

First define the current source in terms of the mesh currents.

I_b - I_a = 3 (Eq. 1)

Now remove the current source to form a supermesh.

Finally, write KVL around the supermesh.

3 I_a + 9 I_b - 15 + 6 I_b + 2 I_a - 18 = 0

5 I_a + 15 I_b = 33 (Eq. 2)

Solving the two equations yields:

I_a = - 600 mA

I_b = 2.4 A