Date Assigned: Monday, February 28, 2005 Date Due: Monday, March 7, 2005
** CHANGED TO Wednesday, March 9 **
Please hand in your lab notebooks on Thursday, March 3 so that
I can grade Labs 1-5.
Reading:
The relevant reading is in Sections 3.1, 3.2, and 3.3.
We will not cover every topic in the text, and
we will emphasize capacitors more than inductors.
The concept of a time constant is very important.
Please solve the following
problems in Chapter 3 of the Bobrow text.
Problem 3.7.
Problem 3.28. What is the time constant for this circuit?
Repeat problem 3.28 for the case that the switch is
opened for t < 0, and the switch is closed
for t >= 0.
What is the time constant for the circuit in this case?
Please solve problem 3.48 in the text.
Note that the voltage source has value 0 volts for t < 0,
and V volts for t >= 0.
Thus it is equivalent to "closing a switch" at time t = 0
to connect an ideal source with value V volts.
Hint:
Write KCL at the "-" input of the op amp.
Use the ideal op amp assumptions.
Also answer the following questions for this circuit.
What is the time constant?
Sketch vo(t).
After a long time, i.e., t >> 0, does this look like
an inverting amplifier? Please explain.
Please analyze the RC circuit that we used in
Lab 6 for the following cases.
Assume that Vs = 12 V, C = 1 microfarad, R = 1,000 ohms,
and Rs = 100 ohms.
Assume that the switch was closed for a long time, and that it is
opened at time t=0.
Find the expression for v(t) and make a sketch of the voltage versus
time.
Label the voltage and time axes on your plot, and indicate the
value and location of the time constant on your plot.
Now assume that the switch is initially opened, and that the
capacitor is initially uncharged (i.e., v(0) = 0 V).
Suppose that the switch is closed at time t=0.
Find the expression for v(t) and make a sketch of the voltage versus
time.
Label the voltage and time axes on your plot, and indicate the
value and location of the time constant on your plot.
Why is the time constant different for the two cases?