How is 'reactance' defined in the context of electricity?

Reactance is defined as the opposition to the flow of alternating current (AC) that is specifically caused by the presence of capacitors and inductors in a circuit. Unlike resistance, which is independent of frequency and affects both direct current (DC) and AC, reactance varies with the frequency of the current. Capacitors create capacitive reactance, which opposes changes in voltage, while inductors produce inductive reactance, opposing changes in current. This frequency-dependent behavior is crucial in AC circuits where the analysis of impedance — the combination of resistance and reactance — is essential.

Understanding reactance is important for effectively managing AC circuit behavior, as it impacts how components interact at different frequencies, affecting overall circuit functionality and performance.