Question

The expression for upper half power frequency is?

(a) (R+√(x^2+4LC))/4πL

(b) (R-√(x^2+4LC))/4πL

(c) (–R-√(x^2+4LC))/4πL

(d) (-R+√(x^2+4LC))/4πL

This question was posed to me in homework.

My question is taken from Bandwidth of an RLC Circuit in portion Resonance & Magnetically Coupled Circuit of Network Theory

Answer 1

The correct answer is (a) (R+√(x^2+4LC))/4πL

Explanation: The narrower the bandwidth the greater the selectivity. At upper half power frequency, XC < XL => -(1/2πf2C)+2πf2L=R. f2 = (R+√(x^2+4LC))/4πL.