Resonance in AC circuit


1) LCR resonance has many applications in the receiver of the radio and T.V.



2) when a system has inductance (L), capacitance (C), Resistance (R), the system shows the oscillation at a particular frequency.



3) This frequency is called natural frequency.



4) The amplitude of oscillation is maximum at this natural frequency. For LCR circuit, we know that




 


5) Now suppose is the resonance frequency then I will be maximum when 



XL - XC = 0


XL = XC











 



Applications of resonance

Resonance is applied in radio and T.V. receiver.

 

A variable capacitor is used, on adjusting the capacitance of the capacitor, then resonance frequency becomes equal to the receiving signal frequency. When it happens the current amplitude becomes maximum for that particular radio station.