Question 3.38: Recall from Chapter 2 that diodes exhibit a junction capacit......

Figure 3.62 shows the equivalent circuit for the case where the diodes are off, suggesting that the conduction of the input through the junction capacitances disturbs the output. Specifically, invoking the capacitive divider of Fig. 3.54(b) and assuming

C_{j1}=C_{j2}=C_{j}, we have

\Delta V_{o u t}=\frac{C_{j}/2}{C_{j}/2+C_{1}}\Delta V_{i n}.           (3.116)

To ensure this “feedthrough” is small, C_{1} must be sufficiently large.