Lab report parts

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Wake Tech Community College Electronics and Computer Engineering

ELC 131 Laboratory Report Requirements

Overview: The laboratory portion of this course is intended to prepare students for careers in the design, development, production, installation, maintenance, and repair of equipment related to electronics and computers. The technician must be able to communicate effectively. Regardless of your career path, the accurate completion of documentation is as important as the hands-on part of the job.

Due date and make-up labs: Every student must submit a laboratory report within one (1) week of the completion of the lab assignment. In the event of an unavoidable absence from a lab meeting, it is the student’s responsibility to complete the missed lab assignment. Work completed outside of the student’s regularly scheduled lab period must be signed and dated by the attending instructor or lab assistant.

Contents and Grading:

1. Presentation and Professionalism (10%): The report should follow the memorandum format as described in the Memorandum Report document. The report should free from grammatical errors, and the tone should be appropriate for a technical report.

2. Pre-lab (10%): Complete any pre-lab requirements before the lab meeting.

3. Data (40%) In the appendix, provide any data tables and graphs that are required in the lab. You may just copy the data tables from the lab word document. However, if there are a lot of calculations, you may find it is easier to create the data tables in Excel.

4. Abstract, Description of Work, and Results and Discussion (20%) The requirements of these sections should be met. The Results and Discussion section should show that the student has given some thought to the lab data and has made some educated statements regarding the lab activity and the data gathered.

5. Questions (20%) Complete the questions in the source document. These questions are to be attached to the memorandum report.

The Memorandum Report

The memorandum report is restricted to a single topic and rarely exceeds one to three typewritten pages. It contains only a few of the elements of the formal report. It is recommended for use between only two people: the author and a single reader who is reasonably acquainted with the subject and whose time should not be spent searching through non-essentials to find the results and conclusions that are of interest. Thus, the author omits materials that the reader is familiar with, such as description of standard tests and equipment.

Originally the term "memorandum" implied something of a temporary nature. This is no longer true, yet there are times when a memorandum is written to make immediately available some information that will later be included in a longer, more formal report. Some of the largest corporations in the nation make use of memoranda.

Printed forms, which vary from company to company, are often used for memoranda. If no form is provided then the report should include the following elements of information.

First Page Heading

The heading on the first page shows the reader at a glance the crucial data on the report. It should include:

a) The title of the report (often called the subject).

b) The serial number of the report, if the report is one of a sequence.

c) The name of the person who wrote the report or the organization that published the report, whichever is appropriate.

d) The person or organization for which the report was prepared, if the report goes to a certain person or organization.

e) The date of publication (or date of submission) of the report.

Abstract

Sometimes called a summary, it helps a busy reader decide whether or not to read the whole report. The abstract also helps in cataloging a report. Since the abstract gives a thumbnail sketch of the report, an abstract of a memo-report should run no longer than half a page; frequently one paragraph describing the entire report (100 words or less) will suffice. Also the abstract should indicate the conclusions of the work so that the reader will be able to evaluate the relevance of the work. In writing the rough draft of the abstract, a writer may ask himself, "What would I write if I had to sum up this report on a 3 x 5 index card?"

Description of Work

A brief, approximately one paragraph long description of the actual work performed which explains where and how the data in the report was obtained.

Results and Discussion

This section summarizes the data gathered in the lab activity. Do not restate information that can easily be found in the data tables, but do discuss the key results of the data and any implications that can be made from the data gathered. This section typically includes conclusions and recommendations.

Appendix

If an appendix is required, it should provide the data (preferably in a tabulated form), graphs, data sheets if available, sample calculations (as required by the instructor), and a list of references.

Data Tables

a) Every table should carry a description title at its top.

b) A table should fit onto a single page, if possible. If a table must spill over to the next page, that page should repeat the title and column headings.

c) A table should be numbered and always referred to in the results and discussion section.

d) A table should always show units in the column headings.

e) The independent variable usually, and logically, goes on the left; the dependent variables go in columns to the right.

Graphs

Only use graphs if they supplement, complement, simplify, or clarify the written work. Graphs are NEVER to be drawn freehand. Graphs should be computer generated. When you decide to plot a graph, you should consider the following:

a) Independent variables should be plotted on the horizontal axis (abscissa) while the vertical axis is only used for the dependent variables.

b) The axes should be labeled with the proper units on each. Use a convenient scale on each axis in such a way that the plot will fill the entire page if possible. The scales on the x- and y-axes may not necessarily be the same.

c) All data points should be included in your plot, even if you have some uncertainty regarding any of them. Points taken under the same test conditions should be identified using the same symbol. If you have to plot more than one curve on the same graph paper, use different symbols, one for each condition.

d) A legend box should accompany each graph, especially if more than one plot is included in the figure.

e) Each graph must be consecutively numbered and titled at the bottom.

Sample calculations

Include a sample calculation for each nontrivial type of calculation. Usually, the sample calculations called for on the data sheets are sufficient. If a data sheet is not included, make your own sample calculations in a labeled box and attach it to the appendix. Most important, show all units in your calculations. It should also be obvious where any number used in your sample calculations comes from i.e. data or graph.

Preparation the Report

1. Reports are to word processed on 8-1/2 x 11 paper. Use 12 point font. (Check with your instructor for preferred font style.)

2. Print on one side of the paper only.

3. Number the pages.

4. The report must be stapled.

If you need more information, you can consult the following references:

1. J.H. Earle, “Engineering Design Graphics,” Prentice Hall, 2004

2. T. A. Sherman and S. S. Johnson, "Modern Technical Writing," Prentice Hall, 1975.

3. R. Hays, "Principles of Technical Writing," Addison Wesley, 1965.

Examples are provided of two well-done memorandum reports which may be used as samples.

Memo Report No. I College of Engineering and Computer Science California State University, Northridge

To: I. A. Ibrahim

From: Jack Smith

Date: October 23, 2004

ABSTRACT

Hardness and tensile strength of a cartridge brass sample were measured as a function of percent cold work (0-60%CW). Both properties increased with the increased percentage of cold work. Recovery , recrystallization, and grain growth characteristics of a 50%CW brass was also investigated by measuring Rockwell Hardness (B Scale) of specimens annealed for 1/2 hour in the temperature range of 200- 700°C. A typical curve with the three distinct regions was obtained. The grain size was also determined for the four highest annealing temperatures and a dramatic increase in the average grain size with temperature was observed.

DESCRIPTION OF WORK

The initial hardness and tensile strength of 70/30 cartridge brass were measured using the Rockwell hardness tester (B scale) and the Instron machine, respectively. The thickness of the samples was successively reduced by rolling up to 60%, while hardness and ultimate tensile strength (UTS) measurements were determined at the different stages of cold work. A 50% CW brass strip was then cut into eight pieces, each was annealed at 200, 250, 300, 350, 400, 500, 600, and 700 °C for 1/2 hr., followed by water quench. The hardness of each sample was finally measured using the Rockwell tester.

Samples for the metallographic observation were polished, etched and observed in a light optical microscope at magnification x 100. The ASTM grain size number, n(l) was determined by comparing the microstructure with a standard ASTM grid, and consequently the average grain size was computed.

RESULTS AND DISCUSSION

The data on hardness and tensile strength as a function of the degree of cold work are shown in Table (1) and Figure 1. The hardness has increased from about 15 to 78 on the Rockwell B scale as a result of 60%CW. The tensile strength has also varied in a similar trend with the increased amount of cold work, The scatter of the data is very small since both properties were taken as the average of several readings under the same test conditions. Furthermore, the data obtained was in rather good agreement with those published in the literature(2,3).

Process annealing of the cold worked samples below 250 °C reduced the hardness very slightly. An abrupt decrease in hardness was observed in the temperature range 250-500°C. Above 500°C the hardness continued to decrease at a very small rate until 700oC has been reached. The three stages of the annealing process, namely recovery, recrystallization, and grain growth, have been established accordingly. This is shown clearly by plotting the data in Table 2 as in Figure 2. The hardness values at high temperatures exhibited greater scatter as is expected when approaching the lower limit of the B scale on the hardness tester.

The grain size of the completely recrystallized samples is also plotted in Figure 2 as a function of annealing temperature. Minor scatter in the values is observed as a result of the statistical errors involved in such measurements(3). However, the results in general are in good agreement with the literature(4).

APPENDIX

Table I. Rockwell Hardness and Tensile Strength of Cartridge Brass at Different Percentages of Cold Work**

% CW

<RB>*

UTSx10-7 (N/m2)

* Average of four hardness readings on Rockwell B scale.

Table 2. Hardness and Grain Size of 50%CW Cartridge Brass as a Function of Annealing Temperature

Temperature oC

<RB>*

Grain size (mm)

200

250

300

350

400

500

600

700

0.010

0.041

0.060

0.154

* Average of four hardness readings.

References

1. L. H. Van V lack, "Elements of Materials Science and Engineering," Addison Wesley, Inc., 1975.

2. R. A. and P. K. Trojan, "Engineering Materials and Their Applications," Houghton

Mifflin Co., 1975.

3. A.G. Guy, “Introduction to Materials Science,” McGraw Hill Book Co., 1972.

4. Metals Handbook, ASM, edited by T. Lyman, 1948.

Memo Report ELC 131 Lab 1 Electronics and Computer Engineering Wake Technical Community College

To: Bill Routt

From: John Smith

Date: August 21, 2011

ABSTRACT

Three basic quantities of electricity, voltage, current, and resistance, were examined. A simple electrical circuit was constructed. This circuit consisted of 1.5 V cells, an incandescent bulb, and a single-pole single-throw switch. A meter was used to measure the quantities voltage and current in the circuit. The values of carbon composition resistors were determined using the EIA/MIL color code scheme. A meter was used to measure the true value of the resistors.

DESCRIPTION OF WORK

A circuit was constructed with 1.5 V cells and an incandescent bulb. The brightness of the bulb with increasing numbers of cells was monitored. With the same circuit, the voltage across and the current through the bulb was measured as cells were added in a series-aiding configuration. The values of five resistors were measured and compared with the nominal value and stated range of the resistors.

RESULTS AND DISCUSSION

The brightness of the bulb with 1, 2, and 3 cells used the voltage source are shown in Table 1. The brightness of the bulb increased with the addition of each cell. This supports the idea that adding cells increases the energy supplied to the circuit.

The voltages across the bulb and the currents through the bulb with 1, 2, and 3 cells used the voltage source are shown in Table 2. The voltage across the bulb and the current through the bulb increased with the addition of each cell. This shows that as more energy is supplied, the potential difference across the bulb and the number of electrons flowing through the bulb increases.

The nominal values, the ranges of resistance as determined by the resistors’ tolerance, and the measured values of 5 resistors are shown in Table 3. Only two of the five resistors were within tolerance. All of the out of range resistors were higher than the maximum value allowed by the tolerance of the resistor. This is most likely due to the fact that the value of carbon resistors increase as the resistors age(1).

APPENDIX

Table 1. Brightness of an Incandescent Bulb with 1, 2, and 3 Cells

Number of series-aiding sources	Observations
1 cell	Barely lit. Nearly impossible to see with room lighting.
2 cells	Slightly brighter. Still difficult to see.
3 cells	Brighter, but not producing much light

Table 2. Bulb Voltage and Current with 1, 2, and 3 Cells

Number of series-aiding sources	Voltage	Current
1 cell	1.45 V	65.8 mA
2 cells	2.90 V	98.4 mA
3 cells	4.35 V	123.5 mA

Table 3. Calculated and Measured Resistor Values

Color code	Nominal value	Minimum value	Maximum value	Measured value	Within tolerance?
Red Black Red Gold	2 kΩ	1.9 kΩ	2.1 kΩ	2.04 kΩ	yes
Orange Orange Brown Gold	330 Ω	313.5 Ω	346.5 Ω	348 Ω	no
Brown Green Brown Gold	150 Ω	142.5 Ω	157.5 Ω	155 Ω	yes
Gray Red Brown Gold	820 Ω	779 Ω	861 Ω	941 Ω	no
Yellow Violet Red Gold	4.7 kΩ	4.46 kΩ	4.94 kΩ	4.99 kΩ	no

Sample Calculations

Minimum value

2 kΩ – (2 kΩ x 0.05) = 1.9 kΩ

Maximum value

2 kΩ + (2 kΩ x 0.05) = 2.1 kΩ

REFERENCES

1. Jack Smith, Clifton Laboratories, http://www.cliftonlaboratories.com/carbon_composition_resistors.htm