Define Resonance in Electrical Circuits?

When the radio or television is tuned to a particular station , then the signals of the other stations are rejected. Actually the receiver does this work through the use of a frequency selective resonant circuits. Different stations transmits at different frequencies and while tuning we adjust the components of a resonant circuit to accept the frequency of a desired station and rejects all others. Due to this application the resonant circuits are known as tuned circuits.
A resonant circuit is a combination of R , L and C elements.this combination may either be series connection or a parallel connection.the following figure shows the general frequency response characteristics of a resonant circuit.It can be seen that the response is maximum at frequency f₀

 called the resonant frequency. The response decreases on both sides of this frequency. Thus the circuit selects the frequencies around f₀ by giving them a "performance treatment" which is the basis of tuning in radio.