In a source follower or common drain amplifier, the voltage gain (AV) is

• In a source follower or common drain amplifier, the voltage gain (AV) is close to option 1.
• This is because these amplifier configurations are designed to have unity voltage gain, meaning that the output voltage closely follows the input voltage without significant amplification.
• The primary purpose of such configurations is often to provide impedance matching or to act as a buffer between different stages of a circuit.

V_gs2 = V₀ - V_s2 =V₀

V_gs1= V₁ - V₀

V₀ g_ds - g_m1 V_gs1 + g_m2 V_gs2 + V₀ g_ds2 = 0

Option 1 is correct.