Lab 2 Report: Nodal Analysis and Thevenin Equivalents
EE 215 AU22 ∙ due week of Oct 31- Nov 04
Names: Jackson Marotta, Zane Hernke, Joyce Peng
Section:
PROCEDURE 1 ∙ Node and Mesh Analysis, Thevenin Equivalent ∙ 25 pts
a. (5 pts) Node Analysis
vcalc = 3.14V
b. (5 pts) Mesh Analysis
icalc = 0.158mA
c. (5 pts) Measurement vs Calculations. Explain any differences from (a) and (b)
d. (5 pts) Nominal Thevenin equivalent seen by 20 kΩ
e. (5 pts) Calculated Thevenin equivalent based on measurements. Compare to (d).
Our nominal values are fairly close to the measured values. Differences could be due to materials.
PROCEDURE 2 ∙ Thevenin Equivalents as Models ∙ 25 pts
a. (5 pts) Measure open/short circuit
b. (5 pts) Draw Thevenin equivalent for battery+series resistor. Calculate the battery’s internal
resistance, then draw the Thevenin equivalent of the battery only.
c. (5 pts) Measure open/short circuit of potato battery
d. (5 pts) Thevenin equivalent of potato battery (without 100Ω)
e. (5 pts) Which is a better battery, and why?
The battery is a better battery because it has a lower internal resistance than the potato.
PROCEDURE 3 ∙ Dependent Sources ∙ 25 pts
a. (5 pts) Measurements & current calculations
vbat = 8.87V
vR1 = 0.023V
vBE = 0.59V
iB = 0.0000015A
vR2 = 3.95V
vCE = 4.90V
iC = 0.000395A
b. (5 pts) Calculate CCCS parameters
c. (5 pts) Redraw circuit as CCCS model
d. (5 pts) iB = 3.5 μA measurements/calculations. Comment on differences between computed
and measured values.
vR1 = 0.07V
vCE_calc = 0.22V
vCE_meas = 0.14V
e. (5 pts) Datasheet comparison (note - 𝛃 may appear as hFE in the datasheet). Comment
on differences.
Our measured voltage from the base to the emitter was very close to the advertised voltage, differing by only
0.06V. For our () value, we were a little farther off, about 12% lower than the desired 300 multiplier. This
could be due to slight discrepancies in our equipment, such as worn out resistors, or the fact that our
battery’s voltage was a bit low.
PROCEDURE 4 ∙ Experiment Design ∙ 25 pts
a. (20 pts) Write an experimental procedure to determine the Thevenin equivalent model for an
LED in the On (light emitting) state. Include a circuit diagram and step-by-step procedure.
b. (5 pts) Execute your procedure and determine model parameters. Check the model when the
LED is in the off state. Comment on how good a model you have.
Our model seems fairly accurate. When we tested the model with a 4.67 kΩ resistor, our measured voltage and the
one calculated through our model were the same.