Reactance

Reactance is the opposition to alternating current produced by capacitors and inductors. Unlike resistance, it depends on frequency and can store and return energy rather than dissipating it as heat.

Capacitive reactance: The opposition a capacitor presents to alternating current, decreasing as frequency increases. It is the capacitor’s contribution to reactance and falls as the signal frequency rises.
Alternating current: Electric current that periodically reverses direction, usually with a time-varying magnitude. Reactance describes opposition specifically in circuits carrying this changing current.
Electrical filter: A circuit that selectively passes or attenuates signals according to their frequency. Frequency-dependent reactance lets filters separate signal components by frequency.
Electrical resistance: The property of a material or component that dissipates electrical energy as heat and opposes current. Resistance dissipates energy, whereas ideal reactance stores and returns energy during each cycle.
Inductive reactance: The opposition an inductor presents to alternating current, increasing as frequency increases. It is the inductor’s contribution to reactance and rises with signal frequency.
Capacitance: A measure of a system’s ability to store electric charge per unit voltage. Capacitance determines how strongly a capacitor opposes alternating current at a given frequency.
LC circuit: A circuit containing an inductor and capacitor that can exchange energy and oscillate. Its frequency response follows the interaction of inductive and capacitive reactance.
Conductance: A measure of how readily a component conducts electric current, equal to the reciprocal of resistance. Conductance describes resistive current flow rather than frequency-dependent energy storage.
Phase angle: The angular difference between two periodic signals or between voltage and current in an AC circuit. Reactance makes voltage and current out of phase, with opposite directions for capacitors and inductors.
Inductance: A property of a circuit that relates changing current to induced electromotive force and magnetic energy storage. Inductance sets the magnitude of an inductor’s frequency-dependent opposition.

Linked from 7 pages