What does the term 'reactance' refer to?

Reactance specifically refers to the opposition that inductors and capacitors provide to alternating current (AC) signals. This opposition is distinct from resistance, which applies to both direct current (DC) and AC. Reactance varies with frequency; for inductors, it increases with higher frequency due to the nature of magnetic fields, while for capacitors, it decreases as frequency increases because the capacitive reactance is inversely related to frequency.

This concept is critical in the analysis of AC circuits, as it helps in understanding how these components behave under different AC conditions. By characterizing the opposition provided by inductors and capacitors, engineers can design circuits that manipulate AC signals effectively, such as in filters and oscillators. In summary, reactance is a fundamental concept in AC circuit analysis, providing insight into how energy is stored and released in reactive components like inductors and capacitors.