Q.The gain of a buffer amplifier is unity. Explain.

A buffer amplifier is a voltage follower in which the entire output is fed back to the inverting input. …

[!TLDR]

A buffer is a voltage follower whose output is tied to the inverting input, giving $V_o = V_{in}$ and a gain of 1.

In a non-inverting amplifier the closed-loop gain is $A_v = 1 + R_f/R_i$. A buffer (voltage follower) is obtained by connecting the output directly back to the inverting terminal, i.e. $R_f = 0$, and leaving $R_i$ effectively infinite (open). Substituting these gives $A_v = 1$. Because the input impedance is very high and output impedance very low, the bu …