ECE 3043 Lecture Exam 1
1. For the circuit shown,
(a) Find the Thevenin equivalent circuit with respect to C1 in terms of the symbolic
component values. Draw the overall equivalent circuit including the capacitor.
(b
...
ECE 3043 Lecture Exam 1
1. For the circuit shown,
(a) Find the Thevenin equivalent circuit with respect to C1 in terms of the symbolic
component values. Draw the overall equivalent circuit including the capacitor.
(b) Find an expression for the current that flows through R2 from right to left at time
t.
(c) Let V1 = 5u(t), R1 = 3 kΩ, R2 = 1 kΩ, R3 = 3 kΩ, R4 = 1 kΩ, and C1 = 0.1 µF.
Solve for the numerical value of the current that flows through R2 from right to
left at time t = 200 µs.
2. Determine the complex gain transfer function T¯(s) = V out/V1. for the circuit shown
below and write it in the space provided. Specify it as a function of the complex
frequency, s, and the symbols for the resistors and capacitor. Write it in standard form
(a gain multipied by a ratio of polynomials in s having constant terms of 1) Determine
the symbolic expressions and the numerical values of the pole and zero frequencies as
well as the high and low frequency gains. On the attached graph, plot the asymptotic
magnitude of the complex transfer function T¯(jω) in decibels as a function of the
frequency f of the source as f varies from 1 Hz to 1 MHz. When making the plot, use
the numerical values given for the resistors and capacitors.
T¯(s) =
T¯(0) =
T¯(∞) =
fp
=
3
=
4
dB
1 10 10
2 4
103 10 105
f (Hz)
6
10
5
Answer the following.
(a) An ammeter is used to measure the current through resistor R4 The ammeter
reads 1.3314 mA. What is the input resistance of the meter? Is this an ideal
meter? Explain.
(b) Design a circuit containing 1 ideal op amp, 1 10 kΩ potentiometer, and any additional resistors that has a gain that varies from −1 to −0.5 as the potentiometer
is turned across its complete range. Draw a schematic of your design.
(c) In terms of the symbolic component values, what resistance would be measured
across R7 by an ideal ohmmeter?
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