ABSTRACT
This chapter begins by discussing instantaneous power in resistors, inductors, and capacitors, followed by the more general case of a circuit that is a combination of these elements. This serves to define real power and reactive power and explain their nature. The chapter defines complex power, justifies its conservation in detail, and illustrates its usefulness in circuit analysis in power factor correction that counteracts the inductive reactive power in a circuit. It discusses the problem of maximum power transfer, first in the case of purely resistive circuits, followed by the more general case in terms of impedances and admittances of a source and a load. The chapter examines the conditions of maximum power transfer from source to a load, first without constraints and then subject to some constraints that may be encountered under certain conditions. Power calculations are generally straightforward but tedious because they involve complex voltages and currents. They are considerably facilitated by utilizing the concept of complex power.
