What is reactance?

Reactance is defined as the opposition to the flow of alternating current (AC) caused by inductance and capacitance in a circuit. Unlike resistance, which dissipates energy in the form of heat, reactance does not consume power but instead stores energy temporarily. It is a crucial concept in AC circuits because it helps determine how the circuit will respond to changes in voltage and current over time.

In practical terms, reactance affects the phase relationship between voltage and current in AC circuits. Inductive reactance, caused by inductors, results in the current lagging the voltage, while capacitive reactance, caused by capacitors, leads to the current leading the voltage. Understanding reactance is essential for analyzing and designing circuits that operate with alternating current, as it directly impacts the performance characteristics such as resonance, impedance, and overall power factor of the system.