# Two Op Amps

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Two op-amp amplifiers are shown below. Assume that the op-amps in these amplifiers are ideal.

For the amplifiers of topology A and topology B, determine R_1 and R_2, respectively, so that they both have a gain of magnitude 10 from v_{IN} to v_{OUT} (i.e. \left|\frac{v_{OUT}}{v_{IN}}\right|= 10).

R_1=

R_2=

The input source v_{IN} to each amplifier is next replaced by the network shown below. With this replacement, now determine the gain of both amplifiers from v_{IN} to v_{OUT}. You should leave your answer in terms of R, R_1, R_2, and R_3, and not reuse your answer from the part above.

**As usual, use R1 for R_1, etc.**

Topology A: v_{OUT}/v_{IN}=

Topology B: v_{OUT}/v_{IN}=

Which of the two amplifier designs would be most likely to faithfully amplify the voltage from a realistic previous stage having a non-zero output resistance?

**You have one attempt:**