FET tuned amplifier with gm = 5 mA/V, rd = 20 kΩ has a

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FET tuned amplifier with g_m = 5 mA/V, r_d = 20 kΩ has a resonant impedance of 20 kΩ. The gain resonance is given by—

1. 200
2. 100
3. 50
4. 25

Correct Option: B

Given, g_m = 5 mA/V, r_d
= 20 kΩ,
Resonant impedance i.e. R_D = 20 kΩ
Now, Gain = g_m (r_d//R_D)
= 5 mA/V (20 kΩ//20 kΩ)
or Gain = 5 × 10^–3 × 10 × 10³ = 50