ECE 220 NETWORK ANALYSIS I FINAL 15S

365 Points Name_____________________________

Instructions: You may use one sheet of notes and your calculator. Fill in the blanks, circle

the correct answer, show all steps of your work, etc. Remember to include units on answers.

Complete each part of the problems.

1. (20) Find the resistance between A and B.

The answer is an integer.

2. (5) How much energy (in Joules) is stored in a 50μF capacitor with a voltage of 80V?

3. (10) I = _____________________

4. (25) Use the Mesh Current method to calculate Ix.

The answer is an integer.

5. (15) Circle only the essential nodes in the circuit at

left in such a way that there are no redundant

circles. How many KCL equations are needed

for this circuit? ______ How many KVL

equations are needed?_______

6. (15) The switch has been open for a long time. The switch is closed at t = 0s.

Calculate ωo. What should the value of Rx be to make the circuit critically

damped?

7. (10) Calculate v(t).

8. (50)

Voltage or Current Value and Units Reason or Calculation

i1(0–)

i2(0–)

v1(0–)

v2(0–)

i1(0+)

i2(0+)

v1(0+)

v2(0+)

i1(∞)

i2(∞)

v1(∞)

v2(∞)

The switch has been open for a long

time. The switch is closed at t = 0s.

Completely fill in the table below.

Give reasons or calculations in the

table for each entry.

9. (25) A laboratory power supply has a voltage of 100V when connected to a

1000Ω resistor, and a voltage of 80V when connected to a 500Ω resistor.

Sketch the Thevenin equivalent circuit for this power supply. What resistor

value connected to the power supply consumes maximum power? How

much power is that in Watts? The answers are not integers; round off.

10. (10) A balanced Y-connected 3-phase generator with a phase voltage of 100V is

connected to a delta-connected balanced 3-phase load that consumes 3.6kW at

0.8pf lagging. Calculate the line current. The answer is an integer.

11. (35) The switch has been open for a long time. The switch is closed at t = 0s.

Calculate v5(t) at 0-, 0

+, and ∞. What is the time constant for t > 0s?

Write the function of v5(t) for t > 0s.

The switch is closed at t=0. Find

12. (40) v(t) = 5cos(100t – 12°) V

Vrms = ______________________v f = ____________________Hz

Vavg = ______________________v T = ___________________s

Vpeak-to-peak = _________________v ω = ___________________radians/s

�⃑⃑� = _______________________v

v(t = 0.008) = _______________v

Average power consumed in a 10Ω resistor connected to this voltage = _____________W

13. (20) iL(0) = 0A. Calculate iL(t) and iC(t).

14. (35)

vX(t) = 90cos(800t + 108°)V Use the Node Voltage method to calculate

the steady state value of iY(t).

(Hint: Use phasor conversion.) (Hint: Use phasor conversion.)

the steady state value of iY(t).

(Hint: Use phasor conversion.)

15. (30) Use a circuit similar to the “Sample op amp circuit” shown to finish this problem.

Design an op amp circuit to produce -10v as output voltage. An ideal op amp,

with a cutoff of -16V and saturation of +16V, will be part of your design. You

can choose as many or as few of the following components (some pictured as

reference) to complete your design: resistors (1kΩ, 2kΩ, 4kΩ, 5kΩ, 10kΩ, and

20kΩ), batteries (1v or 2v), and access to GND.

Sketch your circuit design for -10v output voltage.

Analyze your design to prove it will produce the required -10v output voltage.

Toolbox of Electronic Components

Sample op amp circuit

16. (20) Use Superposition four times to calculate VA.