What property of an AC circuit is defined by the term impedance?

Impedance is defined as the total opposition to current flow in an alternating current (AC) circuit. It encompasses not only the resistance, which opposes the flow of current in a straightforward manner, but also the reactance, which arises from the inductance and capacitance in the circuit. Reactance contributes to the phase difference between voltage and current, making impedance a complex quantity that can be represented as a combination of resistance and reactance.

Understanding impedance is crucial in AC circuit analysis because it affects how much current will flow for a given voltage according to Ohm’s Law, which in the context of AC circuits is represented as V = IZ, where V is voltage, I is current, and Z is impedance. This relationship highlights the importance of impedance in determining the behavior of circuits under AC conditions, thus influencing the design and functioning of electrical systems in aviation and other fields.