Question

Obtain the Thevenin equivalent at terminals a-b of the circuit in.

Answer 1

We find Z_Th by setting the voltage source to zero. As shown in Fig. (a) below, the 8-Ωresistance is now in parallel with the −j6 reactance, sothat their combination gives

Similarly, the 4-Ωresistance is in parallel with the j12 reactance, andtheir combination gives

The Thevenin impedance is the series combination of Z₁ and Z₂; that is,

To find V_Th, consider the circuit in Fig. (b). Currents I₁ andI₂ are obtained as

Applying KVL around loop bcdeab in Fig.(b) gives