Electrical reactance

Opposition to current by inductance or capacitance

In electrical circuits, reactance is the opposition presented to alternating current by inductance and capacitance. It is measured in ohms. Along with resistance, it is one of two elements of impedance; however, while both elements involve transfer of electrical energy, no dissipation of electrical energy as heat occurs in reactance; instead, the reactance stores energy until a quarter-cycle later when the energy is returned to the circuit.

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