5.6 Average Power, Reactive Power and Power Factor¾Maximum Power Transfer
The steady-state AC version of the maximum power transfer theorem is similar to its DC counterpart (but the numbers are complex) and is shown below¾see text pp. 183-185 for its (calculus) derivation
Note that both the (Thevenin) phasor circuit’s voltage VTh and impedance ZTh are complex numbers
The rules for obtaining the Thevenin circuit remain: VTh = Vopen circuit and ZTh = circuit impedance remaining after all independent sources are deactivated
ZLoad = Z*Th for maximum (average) power transfer from the Thevenin circuit to the load¾ RTh = ZTh (magnitude of ZTh) if the load is purely resistive