Resonance is the tendency of a system to oscillate with greater amplitude at some frequencies than at others. Frequencies at which the response amplitude is a relative maximum are known as the system's resonance frequencies. To study the resonance in an RLC circuit, as illustrated in , we can see how the circuit behaves as a function of the frequency of the driving voltage source.
where Irms and Vrms are rms current and voltage, respectively.
The reactances vary with frequency
At some intermediate frequency
The receiver in a radio is an RLC circuit that oscillates best at its