ECE 248
Lab 1 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 diodes
work), what you actually did (e.g. circuit simulation, construction, and testing), noteworthy results (e.g.
the LEDs turned on). The last sentence or two should describe your opinion on how you benefited from
the lab (e.g. feel more comfortable with using a diode).
INTRODUCTION
Briefly give a background (a few sentences) for each of the main topics of Lab 1:
1) Diodes: Briefly describe the importance of diodes and how a diode works in a circuit
2) Half-wave rectifier: Briefly describe the practical application and basic theory of operation of a
half-wave rectifier.
3) Limiter: Briefly describe the practical application and basic theory of operation of a limiter.
EXPERIMENTS AND RESULTS
Provide the following information for each circuit you simulated/built/tested.
Circuit 1: Half-wave rectifier (example is shown on Page 3)

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 1 Report
Spring 2014
Circuit 2: Half-wave rectifier with 1uF capacitor

Circuit schematic, simulated waveform and experimental waveform

Simulated VMAX and VRIPPLE

Estimated VRIPPLE from the formula in Lecture 1

Percent disagreement between the formula result for VRIPPLE and simulation.

Measured VMAX and VRIPPLE, percent disagreement of each measurement with simulation

How good is the agreement between simulation and experiment for VMAX and VRIPPLE?
Circuit 3: Half-wave rectifier with 100 uF capacitor

Circuit schematic, simulated waveform and experimental waveform

Simulated VMAX and VRIPPLE

Estimated VRIPPLE from the formula in Lecture 1

Percent disagreement between the formula result for VRIPPLE with simulation

Measured VMAX and VRIPPLE, percent disagreement of each measurement with simulation.

How good is the agreement between simulation and experiment for VMAX and VRIPPLE?
Circuit 4: Voltage limiter using LEDs

Circuit schematic, simulated waveform and experimental waveform

Simulated VMAX and VMIN

Measured VMAX and VMIN, percent disagreement of each measurement with simulation

How good is the agreement between simulation and experiment for VMAX and VMIN?
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 1 Report
Spring 2014
(Example for Circuit 1 is shown below)
Circuit 1: Half-wave rectifier
D1
50
Load
RS
d1n4002
5 Sine(0 5 60 0 0)
V1
10k
RLOAD
Fig. 1: Circuit diagram for half-wave rectifier.
Load
Maximum=4.4468957V @20.823977mSecs
Channel 1
6
3.5
5
3
4
Amplitude (volts)
Load / V
4
2.5
2
1.5
2
1
1
0
0.5
-1
-0
0
10
20
30
40
Time/mSecs
50
-2
60
10mSecs/div
Fig. 2: Simulated waveform.

3
0
0.005
0.01
0.015
0.02 0.025 0.03
Time (sec)
0.035
0.04
0.045
0.05
Fig. 3: Measured voltage waveform.
Data analysis:
o
The simulated peak voltage is 4.45V, while the experimental result is Vmax = 4.3V.
o
The percent disagreement is (4.3 - 4.45)/4.45 x 100% = -3.4%.
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:

You should have found that the measured VRIPPLE is much smaller for the 100 uF capacitor circuit
compared to the 1.0 uF capacitor circuit. Provide a physical explanation of this observation.
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ECE 248

Lab 1 Report
Spring 2014
You should have found that the ripple voltage formula has frighteningly horrible disagreement (about
130%) for the 1.0 uF capacitor circuit, but reasonable error (about 15%) for the 100 uF capacitor
circuit. What could be a possible reason? Hint: Remember the formula assumes the voltage “droop” is
linear with time.

Your LED circuit produced scope traces with very different shapes depending on the amplitude of the
input sine wave. At 10 VPP input, the LEDs were on and the scope showed a clipped sinusoid
(roughly +/- 2.2 V). At 1 VPP input, the LEDs were off and the scope showed a 1 VPP sinusoid that
was not clipped. Explain what is going on. Hint: The red and green LEDs have an “on voltage” of
about 2 V, unlike normal diodes.

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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