P 6.4-14 The circuit shown in Figure P 6.4-14 has one input, vs, and one output, vo. Show that the output is proportional to the input. Design the circuit so that v_o = 20 v_s.

Figure P 6.4-14

After annotating the circuit

From the rules of op-amps we can write

Write voltage node equations for and

Solve second equation for also plugging in

Now plug this into first equation and again plug in

Collect like terms

So is proportional to ! Now find that produce a gain of 20

Many possible answers.

First of all notice is not in the gain relationship, so it can be any value you wish. Use kΩ values to keep currents low to op-amps. So pick values of that multiply to 19 and pick values of that multiply to 20.

One possible answer is

Other answers are possible!

Dr. Donovan's Classes Page	Dr. Donovan's PH 320 Homework Page	PH 320 Homework Chapter 6 Page
Dr. Donovan's Main Web Page	NMU Physics Department Web Page	NMU Main Page

Please send any comments or questions about this page to ddonovan@nmu.edu

This page last updated on March 15, 2019