What is impedance?

Impedance is defined as the total opposition that a circuit presents to alternating current (AC). It is a complex quantity that encompasses not only resistance (the opposition to current flow in a resistive circuit) but also reactance, which arises from inductors and capacitors in the circuit. Reactance represents the opposition to changes in current and voltage due to the inductive and capacitive elements, and it varies with frequency.

Thus, when considering AC circuits, impedance effectively combines both resistance and reactance into a single measure, allowing engineers and technicians to analyze and design AC circuits accurately. This makes the concept of impedance crucial for understanding how AC circuits operate, predicting their behavior, and ensuring proper design and functionality.

The other choices do not accurately describe impedance. The inverse of resistance pertains specifically to how resistance works, not accounting for reactance. The Q or Quality Factor relates to the efficiency of reactive components and not impedance itself. The power handling capability is about how much power a component can handle and doesn't directly relate to the concept of impedance.