Which of the following statements is NOT true about bandwidth in an RLC parallel circuit?

The correct answer is: Bandwidth is the ratio of quality factor to the resonant frequency, as this statement is not true with regard to parallel RLC circuit.

Concept:

• The bandwidth of the RLC circuit is defined as the range of frequencies for which circuit output voltage (or) current value equals 70.7 % of its maximum amplitude, which will occur at the resonant frequency.
• Bandwidth is defined as the size of the frequency range that is passed or rejected by the tuned circuit.
• Bandwidth can be given in terms of resonant frequency and quality factor and the formula for calculating bandwidth is the same for series and parallel circuits.

The characteristic equation is given as,

The formula for calculating bandwidth is the same for series and parallel circuits.

The bandwidth of a parallel RLC network is given as

• The bandwidth can be given by the ratio of resonant frequency to quality factor.
• Bandwidth is independent of resonant frequency term, though it depends upon circuit parameters (R,L,C).
• At resonance, the imaginary part of the net impedance becomes zero, which makes the input impedance a real quantity. Also, at resonance, the input impedance for a parallel resonant circuit attains a maximum value.
• This is opposite to a series resonance where at resonance, the impedance attains a minimum value.