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Introduction: Electrical Engineering Lab Reports

Writing a lab report is both a journey and a destination. During an experiment, you travel beyond the information in a textbook to a tactile environment. Here, you'll encounter unexpected characteristics about devices and concepts. Once the experiment is finished, you gain insight by analyzing your results. Performing experiments and writing lab reports provide hands-on experiences with engineering concepts and devices.

Definition of a Lab Report

A lab report is an account of an experiment and what was discovered during the experiment. Typically, lab reports present data, discuss results, and provide conclusions. Some lab reports also describe the experiment and the procedures followed. As a student, lab experiments provide you with hands-on experience. Writing about your work in a lab then forces you to think logically about your data. For example, if you get unexpected results from a lab experiment, you'll speculate why you got those results in the report.

Project Notebooks

Project notebooks record your experiments and include information about the procedures you followed and your findings, as well as the successes and failures during an experiment itself. Notebooks also help you remember an experiment's details. If several weeks or months have passed since you actually completed an experiment, reading your entries from that time as you write your report will help you remember the details.

Audience

Readers may or may not know the details of a lab report. You shouldn't assume that they know a test well enough to fill in the report's blanks or that they know anything about the actual lab. Check with your instructor to know who your audience is. To help you describe your lab thoroughly, assume you're writing for a peer in your class, a student who knows what the instruments are, but who doesn't know any of the details of what you're doing. Or, assume you're writing for engineers who will use your information on a project. They may not be familiar with all the terms, so you should explain the lab to them.

Types of Lab Reports

Not all laboratory work requires a report. In fact, at times you may conduct an experiment and only document the numerical results. Other times, you'll elaborate on the experiment's details by formally presenting the procedures you followed and the equipment you used.

Another type of lab report is a project report. A project report is similar to a lab report in that they both present data. However, the difference between the two is often the amount of information conveyed. Project reports usually document more than results. Always check with your instructor to know what type of report you are required to write and what information you should include.

Lab Reports

Lab reports typically cover a more narrow scope than project reports. For example, you may be asked to report only the answers to equations or a specific experiment's results. Lab reports, like their name, report work completed in a laboratory. The format of a lab report may be as simple as filling in blank lines on a worksheet or as complex as writing a full report with an abstract, procedures section, results section, summaries, and conclusions. Lab reports usually don't include references; however, as a student, you may refer to information from your textbook and lectures for some reports.

Project Reports

Project reports typically cover a broader scope than lab reports. In other words, this type of report presents a wider understanding of a specific topic. For example, instead of reporting only the resulting numbers of an experiment, a project report might supply background information or alternate solutions to a problem. Further, a project report does not necessarily document an experiment's results. It may describe a design or concept instead. Because project reports provide a "bigger picture," they usually include references.

Project Reports versus Lab Reports

Project reports and lab reports are like recipes. You need to include certain ingredients to make them succeed. More responsibility is placed on students with project reports than with lab reports. After all, in a project report, students are not always told exactly how to proceed. They may be told solve this problem instead of build this device. You might even say that project reports are more like design projects since they sometimes require you to create designs.

General Format

Lab reports, like other kinds of writing, have an organized format. Organizing your report depends on how the report will be used and what headings your readers expect to find. For example, in industry, an engineer reading a report may be concerned only about a test's results and not the procedures or equipment used. On the other hand, a peer in your class reading your report may need to know what equipment you used or how you conducted your test.

Most lab reports follow a general format. However, you may be required to use different headings or to present your data in a different order. You may also be required to include or exclude specific information. Be sure to check with your instructor before using the format depicted here.

Title Page

A lab report should always include a title clearly identifying the lab. A title should be descriptive and accurate, but not wordy, verbose or too terse. Discussions with several instructors show that no relationship exists between the length or literary quality of a title and the quality of a report. That is, a long title does not reflect how good the report is.

A Brief Glance at Capacitors-Lab Report Number Four: Title Page

Title Page

Abstract

The abstract is extremely important because it helps readers decide what to read and what to pass over. The idea of the abstract is to give readers an honest evaluation of what's in the report, so they can quickly judge whether they should spend their valuable time reading the report. This section should give a true, brief description of what's in the report. The most important purpose of the abstract is to allow somebody to get a quick picture of what's in the paper and make a judgment.

The abstract is a brief summary of your report. Its length corresponds with the report's length. So, for example, if your report is eight pages long, you shouldn't use more than 150 words in the abstract. Generally, abstracts define the lab's objective and the procedures followed. They also include the lab's results.

How to Write the Abstract

Abstracts can be organized in a number of ways. A typical organizational pattern presents the objective of the experiment, briefly lists the procedures followed, and briefly reports the key findings. Depending on the importance of the findings, some abstracts report the results first.

Reporting Objectives

It is preferable to state the objective of the experiment early in the abstract. Ideally, you would report the objective first, then provide a description of what you did, and then report the results.

Reporting Procedures

When you report your procedures in an abstract, you should provide only enough information to accurately report what you did. You want to provide a general overview of the procedures you followed. You don't want to go into any degree of detail, since that would defeat the purpose of providing a brief summary of your experiment.

Reporting Results

When you report the results in an abstract, you do not need to go into great detail. For example, if measurements were taken, you can indicate the value that was obtained. You could also cite numbers or equations. Or you might write what you obtained from the experiment, for example, the value for a capacity.

Example Abstracts

Each of the following examples is an acceptable abstract, although neither reports the results of the experiment. They each describe exactly what the purpose of the laboratory experiment was and each follows the logical order of what was done. Differences exist, however, in the level of detail provided and in the quality of writing.

Abstract

The objective for this laboratory was to examine the time response of an RC circuit through the use of an oscilloscope. There were two separate experiments. The first was to indirectly measure a capacitor. The second consisted of designing a circuit that produced a desired waveform.

Abstract

In this lab we studied first order circuits that contained a capacitor, resistors, and a voltage source or sources. For the first part we studied a simple RC circuit. Using a known voltage, we measured the actual value of a capacitor with a known nominal value with an oscilloscope. In the second part we were to design and assemble a ramp generator. To do this, we used a capacitor, transistor, two independent voltage sources, and two resistors. Our goal was to produce a voltage output waveform resembling a ramp.

Introduction

The introduction provides a rationale for why you are doing an experiment and why the experiment is useful. It sets the framework or overview for the rest of the report. Here, you can also present the problem you are solving and summarize any related research.

An introduction should be an introduction. For instance, if you're going to give a speech, presumably the master of ceremonies will introduce you. He or she will give your name, perhaps provide your background, the title of what you'll talk about, and maybe why you have chosen to give the talk. An introduction to a report works the same way.

How to Write the Introduction

The introduction should always set the framework for the rest of the report. You need to say why you're writing the report and why the report is important. You should also try to put the report in context with relevant work that has been done elsewhere in the discipline. More importantly, you need to inform the reader about what it is you're trying to do and how you're going to do it.

Example Introductions

Each of the following examples uses different approaches to accomplish the same goal. To view example lab report introductions, choose the item below:

Introduction

Resistors, capacitors, and transistors serve very important purposes in society. Society would be drastically different if it had not been for the knowledge, development and uses of these components. As electrical engineering students, it is important that we learn about these circuit elements, how they are used, and the function they perform in different circuits. A better understanding of these circuit elements and how they work is one of the many steps that lead to becoming an electrical engineer.

The current in a wire segment is proportional to the potential difference across the segment. The constant of proportionality is defined as the resistance [1]. Resistors in a circuit determine the current flow and voltage drops across a resistor. Carbon, because of its high resistivity, is usually used for resistors in electronic equipment [1].

Capacitors are devices that store electrical charge. Capacitance occurs whenever electrical conductors are separated by a dielectric [2]. They are used in a variety of ways such as tuning a television or a radio to a desired frequency and even smoothing the flow of current that fluctuates [3]. Inside of a capacitor, two plates are found that have a small distance between them. When a battery is connected to the wires from the plates, current will flow for a short time until the capacitor charges up. An example of a capacitor is a flash attachment for a camera. A capacitor stores energy that is then used for the sudden flash of light.

The function of a transistor is to control the flow of electric current. An NPN transistor, such as the one we used in this experiment, has three leads: the emitter, the collector, and the base [4]. The current passes from the emitter to the collector through the base. Changes in base voltage can cause large changes in current flowing out of the collector [4]. This is how the transistor is used as a switch in the second part of this experiment.

In the first part of the experiment we will try to determine the actual value of a capacitor. To accomplish this we need to take several steps. First, using a known frequency and the nominal value of the capacitor, we will calculate the value for a resistor using the specification that steady state is achieved in half of the period (T1). Using the resistor value we will determine the value of tau graphically by setting the time equal to tau and then determining tau from the graph on the oscilloscope. Finally, with the measured values of tau and the resistor we will find the actual capacitance.

In the second part of the experiment, we are going to assemble a ramp generator which produces a specified output voltage. First, the value of the independent current source must be found. Then, using a voltage source and a resistor, we must implement the independent current source. This current source along with the capacitor, transistor, and independent voltage source should produce the desired output voltage in the form of a ramp.

Introduction

The first electrical capacitor was invented about 250 years ago by the Russian scientist Edward Georg von Kliest and independently by physicist Pieter van Musschenbroech of Leyden. Both were studying the process of storing an electrostatic charge. Their Leyden jar consisted of a stopper glass jar filled with water and a nail or wire through the stopper into the water. The experimenter held the jar with the nail touching a charging device. His body served as the grounding path. The water served as a conductor and distributed the charge over its outer surface, at the inside surface of the jar. On the outside of the glass, an equal opposite charge was induced on the surface of the experimenter's hand. Thus, when the experimenter touched the nail, he received a considerable shock.

In its final form, the water in the Leyden jar was replaced by a metal foil on the inner surface of the jar connected to the rod through the stopper. The outer surface was similarly covered by the metal foil coating. Ben Franklin later showed that when the Leyden jar is charged there is an equal and opposite amount of charge. Franklin is a main force behind the theory and is credited for the understanding of modern capacitors [1]. The modern version of the Leyden jar is known today as a capacitor [4].

The principles introduced in the 18th century with the Leyden jar are still at use in the design of capacitors. Thus the essential design is a sandwich of two plates of conducting material separated by an insulating material, or dielectric. Capacitors differ in the size and shape of the plates as well as in the material used in the dielectric. There are a number of classifications of capacitors (by dielectric) including film, mica, ceramic, and glass, all named electrostatic capacitors because of the charge stored between opposing plates. These are further organized by the package style, i.e. radial or axial, leaded or unleaded. Another classification is the electrolytic capacitors which are made of metals and also have a number of classifications [2].

The capacitance of a capacitor is the measure of its "capacity" to store charge for a given Potential Difference and is the ratio of the amount of charge (Q, measured in Coulombs) on either plate to the Potential Difference (V, in volts) between the plates, or simply C = Q/V, where C has units of Farads [8]. Knowing this relationship and the equation for t in an RC circuit called the time constant, or the time it takes for the charge to number of classifications [2].

Capacitors are second to resistors as the most widely used electronic component [5]. It is important to have an understanding of how electrical components work. The focus of this report will be on capacitors. If not for our understanding of how they work , many things that we are familiar with today would not be possible. Through this experiment we will investigate how capacitors function in an RC circuit. In the first section of the experiment in this paper, we will use a method to find the capacitance value of a capacitor using an indirect approach by choosing a known resistor value and the time constant of the circuit. In the second section we will use our knowledge of Thevinin circuit to replace a current source [6] to investigate the use of an RC circuit along with a transistor as a switch to design and build a ramp generator, or more commonly named a saw-tooth generator [3]. Next a discussion of capacitors will be presented. Finally , in the last section our conclusions are presented.

Experiment

Under the experiment heading, you should describe each step of the lab test. Here, you might also document your goals and the steps taken to accomplish those goals. Basically, you are writing down everything you did during the experiment.

The experiment section tells readers what you wanted to accomplish (to measure a the voltage of a circuit, for instance), what steps you took to accomplish your goals, and what materials and equipment you used to accomplish your goals.

How to Write the Experiment Section

The experiment section is fairly self explanatory. In it, you describe each step of the experiment that you went through in order to complete the tasks. Be sure to write this section in the past tense since you're reporting work you have already completed. This section of the report should be extremely straightforward. You do not need to tell what you found -- that is, you don't need to explain the results of the experiment. Instead, you should explain exactly what you did to get your results.

Example Experiment Sections

Each of the following examples uses different amounts of detail to report the experiment.

Experiment

First of all, we found the resistance, R, in the circuit in Fig.1, using a capacitance of 17.4 nF and a square wave with a maximum of five volts and a frequency of one kHz. Then we attached the oscilloscope in parallel with the capacitor and obtained the graph of the wave in FIG.2.

FIG.1. This circuit was used to measure the values of the resistor, capacitor and the time constant, T. V(t) is the square waveform shown above with a frequency of one kHz and a period of T1.

FIG.2. The waveform for the circuit in FIG.1. The axis is drawn to show how to find T. The value, 3.15 volts, was calculated by setting t=T in the equation Vcap=V*(1-e^-t/T), where V=5volts. By putting 3.15 volts on the y-axis, we can then find T by finding where the graph intersects the x-axis.

We then used this graph to find the time constant, T. Then we found the real capacitance using the value of the resistance and the time constant, T, knowing that T=RxC. In the next part of our experiment, we designed the ramp generator in FIG.3a, that produces an output of five volts and a frequency of 200 Hz. First of all, we found the value of the current source In in FIG.4. Then we added a switch to make the signal periodic, but instead of using a mechanical switch, we used a transistor as a switch because it switches much faster. The switch remains open for half of the period, T2, giving the ramp a chance to develop. Then the switch is closed for the same half of the period, T2, so that the capacitor can discharge, which causes the voltage to drop down to zero. Since we can't implement an ideal current source, we had to use an independent voltage source and a resistor to generate the wanted current In. Using the information above, we built the circuit and connected it to the oscilloscope. Our output on the oscilloscope appeared to be like the graph in FIG.3b. The difference between FIG.3a and FIG.3b is that we cannot have an instantaneous change in voltage across a capacitor. The final step was the measure the current In with an ammeter.

FIG.3. Graph (a) is the ideal output of the ramp generator. Graph (b) is the real output of the ramp generator as shown on the oscilloscope.

FIG.4. Circuit (a) simulates the ramp generator. Circuit (b) is a modified version of (a) using a transistor as a switch. Circuit (c) is the same as in (a) and (b) except a voltage source and a resistor are used to implement the ideal current source In.

Experiment

The first circuit we designed was a simple RC circuit as shown in Figure 1. We were to measure the capacitance of a capacitor, whose nominal value was 17.4nF with an oscilloscope. By setting the frequency to 1khz, the period could be found because it is defined as the inverse of frequency. We still needed to find our resistance. The relation we used was 5xRC=period/2. Since we knew the measure and capacitance, the resistance could easily be found. With the resistance known we then measured the time constant. In order to do this, we let the time equal tau in the relation Vc = V1(1-e-time/tau) which gives Vc= .63Vi. Then by reading on the oscilloscope, tau could be read directly. Finally, by knowing tau = RC we determined the capacitance value.

The second circuit, shown in Figure 2, we designed was a ramp generator that produced an output voltage and a certain frequency. The first thing we needed to do was find a value of an ideal current source to feed the capacitor. We used the relation i = C(dV/dt). With a frequency of 200 Hz the time was found by taking the inverse of the frequency. We then divided this by half the period, or 2, to give the actual time. Then by dividing the voltage by the actual time, gave us our dV/dt. We then solved for the current time from the equation above. In order to make the signal periodic we need to add a switch. This was done using a transistor. The switch remains opened for half a period which allows the ramp to develop. Then the switch closes during the later half of the period, thus discharging the capacitor. It would be hard to design this circuit using an independent current source so we transformed the current source into an independent voltage source.

Results

In the results, you should report what you found. Here, you may or may not include data interpretations. Some readers expect interpretations, or conclusions, to be a separate heading. Check with your instructor for what to include in your results.

The results section documents the test's outcome(s). Here, readers discover what the test measured with exact data. Calculations or equations may also be included.

How to Write the Results Section

Be brief when writing your results. If a lab has more than one finding, report the findings under separate subheadings. Typically, in the results, you present the numerical data of your findings. Be sure not to include details about how you performed a lab. Instead, report only the outcome(s). For example, "The results of the three tests are x, y, and z."

If you are required to interpret your data here, explain how you arrived at those results. You should also include why any data may be incorrect, such as odd occurrences during the test. To read more about interpreting your data, choose the item below:

Example Result Sections

Each of the following examples take different approaches in reporting results. In the first example, the authors provide the reader with extensive explanations. In the second example, the authors provide a much briefer account of the results.

Results

For the first experiment we started off by determining the value of R so as the circuit reaches a steady state within half the time period. Therefore RC equals the period divided by 10. Since the period is simply the inverse of frequency, it was found to be .001 seconds. Therefore RC equals .0001 sec. Because we knew the approximate value for C, R can be determined so that the circuit reaches the steady state. We got 5.74 Kohms through calculations, so we used an R with an actual value of 5.46 Kohms.

With the circuit now assembled and the oscilloscope connected across the capacitor, we looked at the region where T=RxC. At this spot V(t) = V0(1 - e-1 ) and since V0 is 5 volts, V(t) is 3.16 volts. Adjusting the oscilloscope so the signal when 3.16 volts over a vertical marker on the screen, we determined the time by counting the horizontal increments to the spot in which the signal was zero. This information not only gave us the time it took to reach 3.16 volts, but also the RC time constant. We got very close to .0001 sec-1 for RC. Now dividing the time constant by the known R yielded C which turned out to be 18.3 nF.

In the second experiment, the first thing to do was to determine the magnitude of the current supply needed to power the ramp generator. Using the equation V(t) = 1/C*int(i dt), we calculated that i needed to be 36.6 uA to bring the ramp voltage up to 5 volts in half the time period. Assuming that there is a very large resistance across the current source-- an open circuit which we'll call 10 Kohms-- we did a source transformation so we could use a voltage source instead. We found that a .366 voltage source in series with a 10 Kohm resistor would provide the approximate current supply we needed.

After assembling the ramp generator, the oscilloscope was connected across the capacitor to verify that the generator was in fact working. It proved that the ramp was very close to linear and it was peaking at 5 volts just as it should. When the ammeter was connected between the resistor and capacitor, it showed a 40 uA, very close to the 36.6 uA we calculated. The only difference between our generator and an ideal one was that ours didn't go completely to zero between the ramp sections. But it was darn close.

Because the capacitor dumps most if not all of its stored energy on the transistor switch, the energy discharged can be calculated. Since E= 1/2CV2 where C is 18.3 nF and V is 5 V, E comes out to be close to 228 njoules.

Results

In building the first circuit we determined the value of the resistor to be 5.74 KO . The actual value measured was 5.66 KO.

In the end, it was found that the deviation in the value did not hinder the experiment. After completing the construction of the first circuit, we determined the time constant from the oscilloscope. The value was measured at 100u seconds. Since we now had the resistance value off of the resistor and the time constant, we were able to calculate the capacitance. Its value was determined to be 17.66 nF.

Using the same equivalent capacitor from part one, we were able to determine the ideal current. With the 5 volts 200 Hz half saw-tooth wave output along with the 17.66 nF capacitor, we calculated the ideal current to be 35.32 uA. After the second circuit was built, we measured the ideal current to be 35.76 uA. This value is within .5 uA of the calculated current. Observing that the capacitor was charging to the maximum of 5 volts, we determined that the energy per cycle stored in the capacitor was 220.75 nJ.

Discussion and Conclusions

One of the goals of the discussion and conclusions section is to comment on the outcome of what you did. You can also speculate about the implications of what you found. Or even about the methods you used to obtain your results.

Typically, the Discussion & Conclusion sections demonstrate what was learned from the experiment. Here, what's been gained in understanding, both from the experiment itself and from any background reading in preparing the report are emphasized. For example, you might note that the procedure you used was a good method for measuring capacity. As a student, it's not likely that you'll be familiar with as many procedures as a practicing engineer, but you can learn about them by reading textbooks and published reports.

How to Write the Discussion & Conclusions Section

As you write this section, be sure to reflect on your data -- write statements on what you think the data is telling you. You should also include figures as necessary. If you choose to comment on the procedures, you should ask yourself questions such as, "What are the advantages of this method compared to other ways?" "What are its deficiencies, or difficulties compared to other ways?"

Example Discussion and Conclusions

These examples depict different information. In one example, the writers repeat what they did and don't comment on what the numbers mean. In the other example, the writers reflect on their data.

Discussion and Conclusions

The first set of experiments stated a basis for the second by providing an understanding of the capacitor and how it reacts to a circuit. We learned that by changing the resistive value we would change the RC time constant, therefore adjusting the rate in which the circuit would reach a steady state. Because the RC circuit was powered by a square wave generator with a known period, RC was easily adjusted to enable the circuit to reach a steady state within half that time period. The five time constant rule of thumb was observed with the help of the oscilloscope. By calculating the voltage generated when time equaled RC and adjusting the signal on the oscilloscope, Rc was easily determined. Since R was known, C was calculated.

In the second portion of the experiment, we used the same method for adjusting RC for the circuit to reach a steady state as in the first portion. To have the voltage across the capacitor increase linearly, an ideal current source needs to be connected in series. However, current source can be approximated using a voltage supply in parallel with a large resistor. When the circuit was assembled, the wave form generated was very close to ideal by going from zero to five volts on flat ramp and then dropping off almost vertically back to zero.

Although we had some slight difficulty with the first portion, mainly determining the approximate RC and using T=RxC to find the real capacitance, the second portion went off without a hitch. Since we had a better understanding of determining RC so the circuit reaches steady state with a certain time period, it worked without a problem after we had assembled it.

From our background reading we learned how capacitors were developed as well as how widely they are used today. Many of our sources poped on the importance of design and focused on several different types of dielectric material. Some popular examples of capacitors and their applications are flashes and strobe lights, keyboards on computers, coaxial cable, automobile ignitions, radio tuners, and detonation systems for thermonuclear devices--all, essential items for everyday life that many of us take for granted.

Discussion and Conclusions

This experiment enabled us to explore some of the basic characteristics of simple RC circuits. The RC time constant was experimentally determined; the value of the capacitor was implicitly verified; and the voltage response of the circuit under switched conditions was examined.

There are several additional things to be learned from this experiment. The voltage for the circuit in Figure 4 is measured across the capacitor. In this configuration the output voltage is given by :

Since the current is related to the voltage applied to the circuit (i is proportional to Vin), this circuit can be regarded as an integrator [4]. What this means is that the circuit will provide an output that is the time integral of the input signal. For example, if the input were a cosine wave, then the output would be a sine wave.

Another thing to notice about the circuit is that if we vary the frequency of the input voltage from zero to some very high frequency and simultaneously plot the ratio of the output voltage to the input voltage, we would obtain a plot similar to the one shown in Figure 4.

This plot shows that the circuit preferentially passes signals of low frequency. Hence this circuit can be called an RC low pass filter. Conversely if we were to measure the voltage across the resistor instead of the capacitor, this circuit would take on the characteristics of being a differentiator and a high pass filter.

When the circuit was assembled using the transistor switch, the experimentally observed voltage did not agree with the calculated results. One plausible explanation is that the periodic input signal may have caused some degree of capacitive reactance. This would have change the total impedance of the circuit . This extra loading of the non-ideal current source was not included in the original calculations, so they could no longer be considered valid.

One final observation regards the actual shape of the output. When the actual output was observed on the oscilloscope, there was a small amount of time required for the capacitor to discharge. This resulted in a slight curve in the downward going edge of the signal. This is an example of the non-ideal nature of real circuit elements.

References

Lab reports may or may not include references. If you use information from the course textbook, cite it as a reference. You should also cite any IEEE, The Institute of Electrical and Electronics Engineers, Inc. standards used in your report. Check with your instructor to determine which reference style you should use.

How to Write the References Section

The IEEE Citation System uses numbers, usually in square brackets, to denote each source to which you refer. Each source is numbered in the order in which it appears in your report. In the Introduction, for instance, you would refer to your sources as follows:

Nilsson [2] defines capacitors as, "Circuit elements based on phenomena associated with electric fields." By learning about the fundamental behavior of capacitors we can now understand some of the applications of capacitors in real life. For examples, as Kaiser [3] discusses, capacitors can be used in audio instruments for automatic volume control filtering and tone compensation.

[2] James W. Nilsson, "Electric Circuits," Addison-Wesley Publishing Company, Inc., New York, 1993.

[3] Cletus J. Kaiser, "The Capacitor Handbook," Van Nostrand Reinhold, New York, 1993.

References

The IEEE is a citation system. Check with your instructor to see how you should cite your references. The references listed below are examples of the IEEE citation system.

[2] James W. Nilsson, "Electric Circuits," Addison-Wesley Publishing Company, Inc., New York, 1993.

[3] Cletus J. Kaiser, "The Capacitor Handbook," Van Nostrand Reinhold, New York, 1993.

References

The IEEE is a citation system. Check with your instructor to see how you should cite your references. The references listed below are examples of the IEEE citation system.

[2] James W. Nilsson, "Electric Circuits," Addison-Wesley Publishing Company, Inc., New York, 1993.

[3] Cletus J. Kaiser, "The Capacitor Handbook," Van Nostrand Reinhold, New York, 1993.

Graphics

Graphics provide illustrated information to readers. In general, graphics are designed to make it easier for readers to understand your report. Deciding when to insert a graphic depends on the information you need to convey. For example, as you're writing your report, you find yourself struggling to describe a complex concept. Fitting your description within a few paragraphs is impossible, so you decide to create a graphic. Often, graphics are useful when concepts, designs, or processes are too complex or cumbersome to describe in written or oral form.

Perspectives on Lab Reports

In this section, you'll read about how electrical engineers think about lab reports.

Considering Your Audience

When you write a technical report, how much do you assume the reader knows? I think normally, if you're writing, let's say, in the IEEE Transactions - you'd better assume the reader is an electrical engineer. He or she knows what ohms are, what farads are, what a capacitor is, and what an oscilloscope is. But you shouldn't assume that he or she knows anything about the measurement that you're doing.

The Abstract’s Function

An important part of skillful reading, particularly when reading technical material, is sorting out the chaff from the wheat--finding what's important to spend your time reading. When they read a technical paper, most people won't go to a journal, find a paper and sit down and read it. Instead, they'll look at the title and decide if the article sounds interesting or not. If it looks interesting, they'll go to the next step. Some people at that point will read the abstract next, while others might glance at the figures and then look at the abstract. The point is that the abstract becomes a crucial decision maker about whether or not to read the full article. If the abstract looks interesting, then readers would go to the next step of skimming the paper. If that looks good, then they'd read the whole paper. Reading the whole paper takes valuable time. The abstract is one of the steps to devoting a lot of time to the paper. A key thing to remember is that you're not trying to trap people into reading the paper--there's nothing to be gained by that.

How Readers Use Introductions

When I read a report and after I've gone through the abstract and decided that the report looks like something I'd want to read, I'll probably look at the results section. If the results are interesting, then I'll come back and I'll start reading the introduction. As I read the introduction, I'll be looking for information about why the results of the experiment are important.

The Experiment Section's Goal

The most important goal of this section is to explain clearly and precisely what was done to obtain the results. You also need to tell your readers the precise procedures that you followed to obtain those results. In a way, it's like telling the ingredients for a cake without revealing the steps necessary to combine and bake them.

Writing an Effective Results Section

Good results sections are to the point and really talk about the results. They don't go off on a side track discussing the experimental stuff again, and that's the way it should be. You shouldn't be repeating information over and over - except to the extent of reminding the reader, or helping the reader follow what you're doing. Then repetition is okay. A reader should not have to fill in the blanks.

Discussion & Conclusions: Organizational Concerns

Sometimes the discussion and conclusion sections are two separate sections - you'll have a discussion section and a conclusion section. I personally like them together, because the conclusions section can sometimes become a little artificial and doesn't really add anything. So, I like to lump them together and just have one final section.

Project Reports versus Lab Reports

The Value of Lab Work

I can learn a lot from reading and hearing information, but there's something fascinating about actually doing lab work, about creating a functioning electronic system. It's no longer a diagram in a book, but rather components put together…something I wired correctly and it works! That's basic human interest!

Additional Resources

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Introduction: Electrical Engineering Lab Reports

Definition of a Lab Report

Project Notebooks

Audience

Types of Lab Reports

Lab Reports

Project Reports

Project Reports versus Lab Reports

General Format

Title Page

A Brief Glance at Capacitors-Lab Report Number Four: Title Page

Title Page

Abstract

How to Write the Abstract

Reporting Objectives

Reporting Procedures

Reporting Results

Example Abstracts

Abstract

Abstract

Introduction

How to Write the Introduction

Example Introductions

Introduction

Introduction

Experiment

How to Write the Experiment Section

Example Experiment Sections

Experiment

Experiment

Results

How to Write the Results Section

Example Result Sections

Results

Results

Discussion and Conclusions

How to Write the Discussion & Conclusions Section

Example Discussion and Conclusions

Discussion and Conclusions

Discussion and Conclusions

References

How to Write the References Section

References

References

Graphics

Perspectives on Lab Reports

Considering Your Audience

The Abstract’s Function

How Readers Use Introductions

The Experiment Section's Goal

Writing an Effective Results Section

Discussion & Conclusions: Organizational Concerns

Project Reports versus Lab Reports

The Value of Lab Work

Additional Resources