ECE 248
Lab 2 Report
Spring 2014
Title
Author
Your Major, Union College, Schenectady, NY 12308
(if applicable) Your Minor or second Major, Union College, Schenectady, NY 12308
ABSTRACT (MAX = 0.5 pages)
This is the template for your lab report. Replace the text in this template with your own. Margins are 1inch all around. All text is in Times New Roman font with a line-spacing of 1.5. The title is bold-faced,
18 pt, and centered. All other text is in 11 pt font. The author is bold-faced and centered. The author
affiliation is also centered. Each page should have a header and page number. The abstract should be
short (seven lines or so). It summarizes the purpose of your lab work (e.g. better understand how power
supplies work), what you actually did (e.g. circuit simulation, construction, and testing), noteworthy
results (e.g. successful motor speed control). The last sentence or two should describe your opinion on
how you benefited from the lab (e.g. better appreciate power transformers).
INTRODUCTION
Briefly give a background (a few sentences) for each of the main topics of Lab 2:
1) Power transformer: Briefly describe the purpose and operation of a power transformer.
2) Full-wave rectifier: Briefly describe the operation of a full-wave rectifier.
3) Zener diode: Briefly describe the importance of zener diodes and how they work in a circuit.
EXPERIMENTS AND RESULTS
Provide the following information for each circuit you simulated/built/tested.
Circuit 1: Full-wave rectifier (example is shown on Page 3)

Simulated circuit schematic, simulated waveform and experimental waveform

Simulated VMAX, measured VMAX, percent disagreement

How good is the agreement between simulation and experiment?
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ECE 248
Lab 2 Report
Spring 2014
Circuit 2: Full-wave rectifier with 10 uF capacitor

Simulated circuit schematic, simulated waveform and experimental waveform

Simulated VAVG , VPP

Ripple factor based on your simulation results

Measured VAVG and VPP

Ripple factor based on your measured results.

Percent disagreement between measured and simulated ripple factor.

How good is the agreement between simulation and experiment?
Circuit 3: Zener regulator

Simulated circuit schematic, simulated waveform and experimental waveform

Simulated VAVG , VPP

Ripple factor based on your simulation results

Measured VAVG and VPP

Ripple factor based on your measured results.

Percent disagreement between measured and simulated ripple factor.

How good is the agreement between simulation and experiment?
Circuit 4: Adjustable voltage supply

Circuit schematic only

Briefly describe how you confirmed the voltage supply was working properly.

Did you successfully vary the speed of the DC motor?
NOTE:
The circuit schematic and simulated waveform should be taken from your prelab assignment. It might be
easier for you to save your circuit schematic and simulated waveform using the “File >> Save Picture ...”
feature in Simetrix. You can then insert these pictures into your report. Your figures do not have to be in
color – grayscale figures are OK. If possible, keep each figure to be less than or equal to 3 inches across.
This way you can place two figures side by side and save some paper. Include a caption for each figure.
Any calculations can be typed or hand-written (you may attach a separate sheet or include as part of the
main body). Please be neat and clearly label the relevant groups of equations.
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ECE 248
Lab 2 Report
Spring 2014
(Example for Circuit 1 is shown below)
Circuit 1: Full-wave rectifier
D1
d1n4002
V1
5 Sine(0 20 60 0 0)
Load
V2
10k
R1
5 Sine(0 20 60 0 0)
D2
d1n4002
Fig. 1: Circuit diagram for half-wave rectifier.
Load
Maximum=19.411136V @70.839086mSecs
Channel 1
18
30
16
25
14
20
Amplitude (volts)
Load / V
12
10
8
6
2
5
-5
60
70
80
90
Time/mSecs
-10
-0.025 -0.02 -0.015 -0.01 -0.005
0
0.005
Time (sec)
100
10mSecs/div
Fig. 2: Simulated waveform.

10
0
4
-0
15
0.01
0.015
0.02
0.025
Fig. 3: Measured voltage waveform.
Data analysis:
o
The simulated peak voltage is 19.4V, while the experimental result is Vmax = 19.1V.
o
The percent disagreement is (19.1 - 19.4)/19.4 x 100% = -1.55%.
o
There is very close agreement between simulation and experiment for Vmax. Yay!
DISCUSSION
Please provide answers (few sentences each is OK) to the following questions:

Describe at least two major reasons why the peak voltage from your full-wave rectifier was probably
different from your simulation. Hint #1: The first paragraph of Section 4-2 in the textbook might be
helpful. Hint #2: Think about the AC voltage source of your simulation compared to experiment.
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ECE 248

Lab 2 Report
Spring 2014
Describe at least one major reason why the ripple factor for your zener circuit was probably different
from simulation. Hint: Think about zener resistance.

For your adjustable power supply, what is the most likely reason why some students were able to get
a maximum output of 12.0 V, while other students could only get about 11.6V?
Hint #1: The output voltage of the LM317 chip is given by: 𝑉𝑂𝑈𝑇 = 1.25 (1 +
𝑅𝑝𝑜𝑡𝑒𝑛𝑡𝑖𝑜𝑚𝑒𝑡𝑒𝑟
1.2 𝑘𝑜ℎ𝑚
)
Hint #2: Think about component tolerances (e.g. what does a 5% resistor mean?).

Overall, did your circuits work the way you expected?

Were there any peculiarities? For example, you may have observed some spiking, noisy, or resonance
behavior.
CONCLUSIONS
This is where you write about the concepts or any valuable lessons you learned in the lab. If possible,
discuss how they relate to other aspects of the course or to the general field of electronics. Your
conclusion section should NOT be a summary of your results or what tasks you performed. The
conclusion is supposed to reveal what you have learned from your lab experience.
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