Consider the Q sensitivity to R_a and R_b (Equation 7). Note that at K=1 the sensitivity goes to zero. This makes sense because a gain of one means that R_b is a short, and R_a is an open--there are no resistances to vary.

With the simplification of limiting the gain to 1, the equation for Q reduces to:

(10)

As a result of this simplification, our sensitivity equations for this circuit with K=1 degenerate to:

(11)

(12)

(13)

(14)

(15)

This looks quite promising. We only have three sensitivities that aren't a small constant. Two of these sensitivities, Q's sensitivity to R₁ and R₃, are complementary. If these two resistors are made to track closely, for example as a matched set of resistors on a substrate, then the two sensitivities would tend to cancel each other out. Better yet, if we choose R₃=R₁ then the Q sensitivities to R₁ and R₃ go to zero.

Of course, these resistors will not be identical and, therefore, the sensitivities will not be exactly zero. Let's look at a case where these are five percent tolerance resistors (the real cheap resistors), and push them to worst case extremes. In this case the resulting sensitivity is:

(16)