## Question:

Find ${ v }_{ 0 }$in the op amp circuit of Fig. 5.92.

## Step-by-step

The output of the first op amp (to the left) is 6 mV. The second op amp is an inverter so that its output is

$v_{o}^{\prime}=-\frac{30}{10}(6 \mathrm{mV})=-18 \mathrm{mV}$

The third op amp is a noninverter so that

$v_{o}^{\prime}=\frac{40}{40+8} v_{o} \quad \longrightarrow \quad v_{o}=\frac{48}{40} v_{o}^{\prime}=\underline{-21.6 \mathrm{mV}}$