How does a resonant circuit respond to an external driving frequency?

A resonant circuit responds to an external driving frequency by either amplifying or attenuating the signal.

When an external driving frequency is applied to a resonant circuit, the circuit responds by either amplifying or attenuating the signal. This response is determined by the resonance frequency of the circuit, which is the frequency at which the circuit has the highest impedance. If the driving frequency is equal to the resonance frequency, the circuit will amplify the signal, as the impedance of the circuit is at its highest. However, if the driving frequency is not equal to the resonance frequency, the circuit will attenuate the signal, as the impedance of the circuit is lower.

The amount of amplification or attenuation depends on the quality factor (Q) of the circuit. A high-Q circuit will have a narrow bandwidth and will amplify the signal more at the resonance frequency, while a low-Q circuit will have a wider bandwidth and will attenuate the signal more at frequencies away from the resonance frequency.

Resonant circuits are commonly used in radio and television receivers, where they are used to select a specific frequency from a range of frequencies. They are also used in electronic filters, where they can be used to remove unwanted frequencies from a signal.