ELEC 226: Homework Assignment 9

ELEC 226, Spring 2003
Prof. Rich Kozick

Homework 9
REVISED

Date Assigned: Wednesday, March 19, 2003 and revised after class
Date Due: Monday, March 31, 2003

Reading: Continue to study Chapter 7, all sections. For March 26, begin reading Chapter 8, Sections 8.1 and 8.2.
Exam 2 is scheduled for Monday, March 31 on the course syllabus. However, we discussed moving the date for Exam 2 to Monday, April 7. Please let me know by Friday, March 21, if you have any objections to this change in the date of Exam 2. The topics for Exam 2 will include Chapters 7 and 8.
** Exam 2 is on Monday, April 7. **
Please solve the following problems in Chapter 7 for Monday, March 31. I suggest that you try to solve as many of these as you can by March 26, so that you can ask questions.
7.34 (click here for solution to 7.33)
7.42
7.46 (change the 52 V source to 32 V)
7.52 (change the 1 kohm resistor to 6.8 kohm and the 0.025 microF capacitor to 0.2 microF)
7.56
7.74.

** Problem 7.74 will be due on Wednesday, April 2. **
There may be some problems from Chapter 8 on Homework 10 that will be due on April 2.
Please answer the following question for Monday, March 31. Figure 1 contains a slightly more general version of the clock circuit from Lab 4, where R_a and R_b may not be equal. Assume that the op amp is powered so that -10 V <= v_out(t) <= +10 V, and let T denote the period of the waveform produced by the oscillator circuit. Click here for Figure 1
- Find the formulas for the capacitor voltage, v_c(t), during the time intervals 0 <= t <= T/2 and T/2 <= t <= T. Assume that the circuit is in "steady-state" at time t=0, i.e., the circuit has been oscillating for a long time before t=0. Your formulas will be a function of all of the resistor and capacitor values in the circuit (R, C, R_a, R_b).
- Use your results for v_c(t) to find a formula for the period, T, as a function of the resistor and capacitor values in the circuit.
- Sketch v_out(t) and v_c(t) versus time, and indicate the effects of the circuit parameters on the amplitudes and period in your plot.
- How should R_a and R_b be chosen so that v_c(t) is close to a triangle wave? Please explain based on your formulas for v_c(t).
Lab notebooks will be collected on Thursday, April 10, and I will look at Labs 3, 4, and 5.

Thank you.

Homework 9 **** REVISED ****

Homework 9
REVISED