Question

The bandwidth of an RF tuned amplifier is dependent on Q-factor of

• A. \( \text{Tuned output circuit} \)
• B. \( \text{Tuned input circuit} \)
• C. \( \text{Operating point} \)
• D. \( \text{Output, input circuits and quiescent point} \)

Hint:

In RF tuned amplifiers, always associate bandwidth with the **Q-factor of the tuned circuit**, especially the **output circuit**, as it governs the frequency selectivity. Use the relation: \[ \text{Bandwidth} = \frac{f_0}{Q} \] to estimate or understand behavior in such circuits.

Answer 1

The Correct Option is A

In RF tuned amplifiers, the **bandwidth** is determined by the **resonance characteristics** of the output LC (inductor-capacitor) tuned circuit. The **Q-factor (quality factor)** of the tuned output circuit defines the sharpness of the resonance, and hence the **bandwidth**: \[ \text{Bandwidth} = \frac{f_0}{Q} \] Where: - \( f_0 \) is the resonant frequency - \( Q \) is the quality factor of the tuned output circuit A higher Q implies a narrower bandwidth and sharper tuning, which is critical in RF applications. Therefore, the bandwidth is primarily determined by the Q of the **tuned output circuit**.