EE 200
Prof. Rich Kozick
Spring, 1997

EE 200: Homework Assignment #6

Date Assigned: Friday, February 21, 1997
Date Due: Friday, February 28, 1997 at 8 AM

Reading: Please read parts of Chapter 4 as follows. Read section 4.1 for the definition of dependent sources, but don't worry about the details in the examples. Read section 4.2 for the definition of an amplifier, but again don't worry about the various definitions of gain, etc. We will concentrate on applications of op amps, which are discussed in sections 4.3-4.5. We will not cover all of the details in the text, in particular don't worry about the computations of and .

Problems: Please work on the following problems.

1. Using the op amp model shown below, show that the ``buffer'' operates according to . Note that the buffer is connected so that . Briefly explain why if A is very large, then and .

   [CIRCUIT DIAGRAM NOT AVAILABLE -- SEE PAPER COPY]

2. Find in the circuit below. (Hint: Look for voltage dividers and the buffer circuit!)

   [CIRCUIT DIAGRAM NOT AVAILABLE -- SEE PAPER COPY]

3. Design an op amp circuit such that the output voltage is one-fourth the input voltage, i.e. . Hint: You may need more than one op amp.
4. Consider the electronic ohmmeter shown on the back of this page. To use the ohmmeter, an unknown resistance R is connected as shown, and then the value of R is obtained by measuring the voltage and then computing .

   [CIRCUIT DIAGRAM NOT AVAILABLE -- SEE PAPER COPY]

   1. Since is always within the range -10 volts to +10 volts, what is the maximum value of R that can be measured with this circuit?
   2. How can the circuit be modified in order to measure resistance values up to 100 k? Explain the reasoning behind your modification, and explain how the value of R is computed from in your circuit.
5. Please do the following problem.

   [PROBLEM STATEMENT NOT AVAILABLE -- SEE PAPER COPY]

 
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