 Solution

ID: past-exam-of-the-physics-a-course-of-the-university-of-cambridge/2012/paper-1/section-d/d13/b/solution

Let

V_{B}

be the non-inverting input voltage. The feedback divider gives

V_{B} = V_{out} / K

. With

s = iω

, current conservation at this wavefunction node gives

(V_{A} - V_{B}) / R_{2} = s C_{2} V_{B}

, because the amplifier input draws no current. Hence

V_{A} = \frac{V _{out}}{K} (1 + iω R_{2} C_{2}) .

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