Download Midterm Exam 1 - Electrical Eng: Circuit Parameters & Thevenin Equivalents and more Exams Microelectronic Circuits in PDF only on Docsity!
EE 40
Midterm Exam
February 20, 2003
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Problem 1: 15 Points Possible
Problem 2: 5 Points Possible
Problem 3: 15 Points Possible
Problem 4: 15 Points Possible
Problem 5: 15 Points Possible
Problem 6: 10 Points Possible
Problem 7: 15 Points Possible
Problem 8: 10 Points Possible
Total: 100 Points Possible
The memory components of many personal computers require voltages of -12V, 5V, and 12V all with respect to a common reference terminal (ground).
Find R 1 , R 2 , and R 3 in the circuit below so that (when nothign additional is attached to the circuit)
- The power generated by the voltage source is 48 mW
AND
- V 1 = 12 V, V 2 = 5 V, and V 3 = -12 V with respect to ground.
Refer to Problem 2. Suppose I find out that the voltmeter has an internal resistance of 20 M ohm and the ammeter has an internal resistance of 2 ohm.
So, the answer from Problem 2 is not the true Thevenin equivalent.
I want to know how the actual Thevenin parameters, which we will call V T(actual) and RT(actual), compare to the guesses from Problem 2, which we will call VT(measured) and R T(measured).
a) Which internal resistance (the voltmeter resistance or the ammeter resistance) accounts for most of the difference between the actual and measured parameters?
b) Should VT (actual) be higher, lower, or about the same as VT(measured)? Should R T(actual) be higher, lower, or about the same as RT(measured)?
c) Neglect the effect of the meter which does not make much of a difference, and find VT (actual) and RT(actual).
Find the Thevenin equivalent circuit as measured at terminals a and b, for the circuit below.
Consider the RC circuit below, which models a digital logic gate.
Wehn changing Vin from logic 1 (5 V) to logic 0 (0 v) and back to perform different computations, we want to make sure that there is enough time between input changes to allow the output, Vout, to fully respond.
Specifically, we would like to ensure that Vout reaches the minimum value recognizable as logic 1 after the input steps from low to high (0 V to 5 V). This value, VIH, is 3.5 V.
Also, we would like to ensure that Vout discharges to the maximum value recognizable as logic 0 after the input steps from high to low (5 V to 0V). This value, VIL is 11.5 V.
Determine the amount of time it takes for the discharged capacitor to charge to 3.5 V, and the amount of time it takes for the fully charged (5 V) capacitor to discharge to 1.5 V.
Consider the circuit below, where the capacitor is discharged for t <= 0.
a) Find Vout(t) = 2 V (constant), for t>=0.
b) In one word, what operation does this circuit perform on Vin?
