Reactance

Reactance is a concept from physics and engineering that describes how certain components in an electrical circuit oppose changes in current or voltage. It arises from inductors and capacitors. Inductors resist sudden increases or decreases in current due to their magnetic fields, while capacitors resist changes in voltage because of stored electric charge. This opposition causes the circuit's behavior to differ from simple resistance, especially at different frequencies. In essence, reactance acts like a barrier that influences how alternating current flows, affecting the timing and amplitude of signals without dissipating energy like resistance does.