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The voltage gain for the given common source FET circuit is: FET Parameters Y os = 10 μS Y fs = 3000 μS Options A. -3 B. -7.9 C. 2.54 D. -5 Solution Given: Yfs = gm = 3000 μS = 0.003 S Yos = gds = 10 μS Drain resistance of the FET: ro = 1 / gds ro = 1 / (10 × 10^-6) ro = 100 kΩ Given circuit resistances: R D = 2.7 kΩ R S = 2.7 kΩ Since capacitor C 2 bypasses R S , the source is AC grounded. Therefore the voltage gain for a common-source amplifier is: Av = - gm (RD || ro) Calculate parallel resistance: RD || ro = (2.7k × 100k) / (2.7k + 100k) ≈ 2630 Ω Voltage gain: Av = -0.003 × 2630 Av ≈ -7.9 Correct Answer: B. -7.9