What is the resonant frequency in an electrical circuit?

The resonant frequency in an electrical circuit is defined as the frequency at which the capacitive reactance (the opposition to current flow caused by a capacitor) equals the inductive reactance (the opposition to current flow caused by an inductor). At this unique frequency, the circuit can efficiently oscillate, leading to an increase in current and voltage amplitude.

At resonance, the reactive components (capacitors and inductors) effectively cancel each other out, resulting in a purely resistive circuit at that specific frequency. This condition results in resonance, where the impedance is minimized, and the circuit responds with maximum energy transfer.

Understanding this concept is crucial when analyzing circuits that include both inductances and capacitances, especially in radio frequency applications, filters, and oscillators.

In contrast, the choices regarding maximum or minimum frequency are not reflective of how resonant frequency is determined. Resistance being at a maximum does not correlate with the definition or conditions for achieving resonance within a reactive circuit.