The unity follower (or voltage follower) is an op amp circuit that provides a gain of unity (1) with no polarity or phase reversal.
For an ideal op amp,
\(\boxed{v_o = v_i}\)
Closed-loop voltage gain \(A_v\)
\(\boxed{A_v = \frac{v_o}{v_i} = 1}\)
Such a circuit has a very high input impedance and is therefore useful as an intermediate-stage (or buffer) amplifier to isolate one circuit from another. The voltage follower minimizes interaction between two stages and eliminates interstage loading.
