If the resistance in parallel with a parallel resonant circuit is reduced, the bandwidth
A. Disappears
B. Becomes sharper
C. Increases
D. Decreases
Answer: Option C
Solution (By Examveda Team)
Let's understand this concept step by step.A parallel resonant circuit consists of a resistor (R), an inductor (L), and a capacitor (C) connected in parallel. It resonates at a particular frequency called the resonant frequency.
The bandwidth is the range of frequencies around the resonant frequency over which the circuit responds effectively. A narrow bandwidth indicates high selectivity, while a wide bandwidth indicates lower selectivity.
The selectivity of a parallel resonant circuit is measured by its Quality Factor (Q-factor). For a parallel resonant circuit, the Q-factor is directly proportional to the parallel resistance (R).
The relationship between bandwidth and Q-factor is:
Bandwidth = Resonant Frequency / Q-factor
This means that bandwidth is inversely proportional to the Q-factor.
When the parallel resistance is reduced, the Q-factor decreases. As the Q-factor decreases, the bandwidth increases, making the resonance curve broader and the circuit less selective.
Therefore, reducing the resistance in parallel with a parallel resonant circuit increases its bandwidth.
Hence, the correct answer is Option C: Increases.

Q=R✓C/L, So if we decrease the resistance then Q reduces as a result the BW will increase