Electrical resonance

[1] Resonant circuits exhibit ringing and can generate higher voltages or currents than are fed into them.

Resonance is used for tuning and filtering, because it occurs at a particular frequency for given values of inductance and capacitance.

Parallel resonance or near-to-resonance circuits can be used to prevent the waste of electrical energy, which would otherwise occur while the inductor built its field or the capacitor charged and discharged.

, in which f is the resonance frequency in hertz, L is the inductance in henries, and C is the capacitance in farads, when standard SI units are used.

The quality of the resonance (how long it will ring when excited) is determined by its Q factor, which is a function of resistance:

The RLC part of the name is due to those letters being the usual electrical symbols for resistance, inductance and capacitance respectively.

The main difference stemming from the presence of the resistor is that any oscillation induced in the circuit decays over time if it is not kept going by a source.

Some resistance is unavoidable in real circuits, even if a resistor is not specifically included as a separate component.

Inductors are typically constructed from coils of wire, the resistance of which is not usually desirable, but it often has a significant effect on the circuit.

A series RLC circuit has resistance of 4 Ω, and inductance of 500 mH, and a variable capacitance.

This article incorporates public domain material from Federal Standard 1037C.