Download Lab1 report template

ECE 248
Lab 1 Report
Spring 2015
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
Give brief 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 waveforms each with a figure number
and title.

Simulated VMAX, measured VMAX, percent disagreement

How
good
is
the
agreement
between
1
simulation
and
experiment?
ECE 248
Lab 1 Report
Spring 2015
Circuit 2: Half-wave rectifier with 1uF capacitor

Circuit schematic, simulated waveform and experimental waveform each with a figure number
and title.

Simulated VMAX and VRIPPLE

Estimated VRIPPLE from the formula in lecture.

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 each with a figure number
and title.

Simulated VMAX and VRIPPLE

Estimated VRIPPLE from the formula from lecture

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 each with a figure number
and title.

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 pre-lab assignment. From the
grapher view generated form the transient analysis use edit | copy graph. You can then insert these
pictures into your report 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 2015
(Example for Circuit 1 is shown below)
Circuit 1: Half-wave rectifier
Fig. 1: Circuit diagram for half-wave rectifier.
Channel 1
6
5
Amplitude (volts)
4
3
2
1
0
-1
-2
Fig. 2: Simulated waveform.

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 and refer
to the graphs from your results by figure number..
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ECE 248

Lab 1 Report
Spring 2015
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? Refer to the results of calculations, simulation
results by figure number, and experimental results by figure number.

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. Give a brief
discussion of the construction techniques used. 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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