Sir Ken Robinson

https://www.youtube.com/watch?v=iG9CE55wbtY&feature=youtu.be

A professora: O que você está desenhando?

A garota disse: Estou fazendo um desenho de Deus.

A professora disse: Mas ninguém sabe como é Deus.

A menina disse: Eles vão, em um minuto.

As crianças vão se arriscar.

Se eles não sabem, eles tentarão.

Eles (crianças) não têm medo de estar errados.

Estar errado não é necessariamente a mesma coisa que ser criativo.

O que sabemos é que, se você não estiver preparado para errar, nunca encontrará nada original, se não estiver preparado para estar errado.

Eles ficam com medo de estar errados.

E agora estamos administrando sistemas nacionais de educação em que erros são a pior coisa que você pode cometer.

Se você pensar bem, todo o sistema de educação pública em todo o mundo é um processo demorado de entrada na universidade.

E a consequência é que muitas pessoas altamente talentosas, brilhantes e criativas pensam que não são, porque cantam

bom na escola não era valorizado ou era realmente estigmatizado.

"Não crescemos em criatividade, nós crescemos fora dela."

"We don't grow into creativity, we grow out of it."

Sir Ken Robinson

Suddenly. degrees aren't worth anything.

it's a process of academic inflation.

We need to radically rethink our view of intelligence.

We know three things about intelligence: it is diverse; it is dynamic; it is distinct.

Creativity which I define as the process of having original ideas that have value.

Do schools kill creativity? | Sir Ken Robinson

https://www.youtube.com/watch?v=iG9CE55wbtY&feature=youtu.be

But if you ask about their education, they pin you to the wall,

because it's one of those things that goes deep with people, am i right?

Like religion and money and other things.

We have a huge vested interest in it, partly because it's education that's meant

to take us into this future that we can't grasp.

If you think of it, children starting school this year will be retiring in 2020+60.

Nobody has a clue, despite all the expertise that's been on parade ...

what the world will look like in five year's time. And yet, we're meant to be educating them for it.

So the unpredictability, I think, is extraordinary.

Children have extraordinary capacities for innovation.

All kids have tremendous talents, and we squander them, pretty ruthlessly.

creativity is as important in education as literacy, and we should treat it with the same status.

Great story: I little girl who was in a drawing lesson.

The teacher said this girl hardly ever paid attention, and in this drawing lesson, she did.

The teacher was fascinated. She went over to her and she said:

The teacher: What are you drawing?

The girl said: I'm drawing the picture of God.

The teacher said: But nobody knows what God looks like.

The girl said: They will in a minute.

Kids will take a chance. If they don't know, they'll have a go. They (kids) are not frightened of being wrong.

Being wrong is not necessarily the same thing as being creative.

What we do know is, if you're not prepared to be wrong, you'll never come up with anything original if you're not prepared to be wrong.

They become frightened of being wrong.

And we're now running national education systems where mistakes are the worst thing you can make.

12:03
If you think of it, the whole system of public education around the worlds is a protracted process of university entrance.

And the consequence is that many highly talented, brilliant, creative people think they're not, because the sing they were good at school wasn't valued or was actually stigmatized.

"We don't grow into creativity; we grow out of it."

Damn, Sir Ken Robinson has sadly passed away, what an incredible man.

"We don't grow into creativity, we grow out of it."

https://www.youtube.com/watch?v=ZT3QpUfEg1Q 54:42 / 1:04:52

Sir Ken Robinson: "Reimagine Learning that Can Change the World" –

Reimagine Education

Tarefa: tirar a porca do tubo.

Estamos aprendendo as coisas certas na escola?

Participe da discussão sobre nossa educação.

Tudo que as pessoas precisavam para resolver o problema estava na sala.

Todos os recursos que precisavam estavam lá.

As pessoas que o resolveram viram os recursos que estavam disponíveis e fizerem uso deles.

As pessoas que não resolveram o problema não incluíram os recursos disponibilizados no enquadramento do problema e/ou da solução.

Muitas das pessoas viram a garrafa de água e a taça de fruta e, porventura,

acharam simpático, mas não os envolveram na resolução do problema, eventualmente por não quererem perder tempo, centraram-se de imediato na tarefa de resolver o problema.

As pessoas que o resolveram fizeram uso de tudo o que lhes foi disponibilizado.

Opdracht: haal het nootje uit de koker.

Leren we wel de juiste dingen op school?

Discussieer mee over ons onderwijs.

Independentemente da classificação que o aluno obtenha na prova escrita, poderá haver lugar à realização de uma confirmação oral (prova oral) individual dos conhecimentos demonstrados no teste ou exame e/ou para defesa de classificação ou para aferição da nota final; nas provas orais deverão contar com a participação, sempre que possível, de pelo menos dois docentes da UC.

"A principal meta da educação é criar homens que sejam capazes de fazer coisas novas, não simplesmente repetir o que outras gerações já fizeram. Homens que sejam criadores, inventores, descobridores. A segunda meta da educação é formar mentes que estejam em condições de criticar, verificar e não aceitar tudo que a elas se propõe."

Jean Piaget

Pensar como um físico

Thinking like a physicist

Planck's intensive quest for an understanding of the black-body radiation spectrum followed a pattern that you have seen before in your study of physics. Planck’s first step was a trail-and-error one, and this initial goal was limited to finding a mathematical function that would fit the experimental results. His search was motivated in large part by the steady improvement in the precision of the available measurements – a precision that gave good hope that only one plausible function would fit the date well.

Planck did not embark on even this relatively modest effort without background provided by others. He knew that the desired function had to be consistent with Wien’s formula at short wavelengths and with the Rayleigh-Jeans function (equation 40.5) at long wavelength (because those functions did fit the experimental results in those ranges).

Planck could not be content merely with having found the function given by equation 40.7. He had to achieve an understanding of why this function fit the data. In searching for this understanding, he relied on his profound knowledge of statistical thermodynamics. As the famous chemist and bacteriologist Louis Pasteur out it, “In the field of observation, change favors only the prepared minds.”.

Planck’s search was successful – to a pint. As we have seen, he was able to show that the function was not merely a mathematical description of the experimental data but could be derived from fundamental principles of statistical thermodynamics – except that the derivation required a single assumption that he could not justify. The search for justification is the subject of much of the rest of this chapter. But though Planck did not himself succeed in finding the justification, he made the crucial contribution of isolating what he could not understand on basis of acceptable physical principles, thus making it possible for others to focus their efforts.

Conceitos e atitudes fundamentais em Física

http://w3.ualg.pt/%7Ejlongras/Conceitos-e-atitudes-fundamentais-em-Fisica.pdf

Os seres humanos anseiam por certezas absolutas e aspiram a elas. Contudo, a história da Física ensina-nos que o máximo que podemos esperar são melhoramentos sucessivos da nossa compreensão dos fenómenos naturais e, consequentemente, do universo, sempre com a limitação de sabermos que a absoluta certeza nos escapará.

A Física tem vindo a mudar o nosso conhecimento sobre o modo como a Natureza se funciona. Os Físicos procuram descrever os fenómenos naturais com a ajuda de modelos simples. A observação e a experimentação são as chaves mestras do nosso conhecimento sobre o mundo físico. Várias ferramentas são essenciais nesta tarefa: uma mente curiosa e a criatividade, a Matemática, e métodos e aparelhos de medida. Os métodos e os aparelhos de medida, combinados com a lógica e a razão (a formulação de ideias/teorias em Física envolve certas quantidades de pensamento “puro” e de imaginação), permitem que a descrição e a interpretação dos fenómenos possam ser feitas de forma objetiva. Por mais popular e criativa que seja uma teoria ela só corresponderá a uma descrição válida de um dado fenómeno quando esta tiver uma descrição físico-matemática. Porém, o teste de qualquer teoria é sempre a Natureza e/ou a experimentação.

A Física, e a ciência em geral, é mais do que um corpo de conhecimentos, é uma atitude, uma forma de pensar. Com toda a persistência, procuram fendas na armadura dos conhecimentos vigentes: o cientista deve ter um espírito crítico apurado, e não confiar cegamente nas afirmações das sumidades, tendo presente que os cientistas são primatas e, portanto, muito propensos a hierarquias de domínio. Em cada geração há sempre um grupo de cientistas que não se contentam em deixar as coisas como estão. A Física dá, por vezes, as mais elevadas recompensas àqueles que convictamente refutam convicções estabelecidas.

O bom cientista não insiste na validade da sua teoria, mas sim na sua utilidade. Nenhuma teoria, por muito bem concebida ou considerada que esteja, poderá suportar a existência de um só facto importante que seja contraditório. O que interessa não é se “é verdadeira?”, mas sim “funciona?”.

Experiments in Electronics Fundamentals and Electric Circuits Fundamentals To Accompany Floyd, Electronics Fundamentals and Electric Circuit Fundamentals by David Buchla (z-lib.org)

Introduction to the Student

Preparing for Laboratory Work

The purpose of experimental work is to help you gain a better understanding of the principles of electronics and to give you experience with instruments and methods used by technicians and electronic engineers. You should begin each experiment with a clear idea of the purpose of the experiment and the theory behind the experiment. Each experiment requires you to use electronic instruments to measure various quantities. The measured data are to be recorded, and you need to interpret the measurements and draw conclusions about your work. The ability to measure, interpret, and communicate results is basic to electronic work.

Preparation before coming to the laboratory is an important part of experimental work.

You should prepare in advance for every experiment by reading the Reading, Objectives, and Summary of Theory sections before coming to class. The Summary of Theory is not intended to replace the theory presented in the text—it is meant only as a short review to jog your memory of key concepts and to provide some insight to the experiment. You should also look over the Procedure for the experiment. This prelab preparation will enable you to work efficiently in the laboratory and enhance the value of the laboratory time.

This laboratory manual is designed to help you measure and record data as efficiently as possible. Techniques for using instruments are described in many experiments. Data tables are prepared and properly labeled to facilitate recording. Plots are provided where necessary. You will need to interpret and discuss the results in the section titled Conclusion and answer the Evaluation and Review Questions. The Conclusion to an experiment is a concise statement of your key findings from the experiment. Be careful of generalizations that are not supported by the data. The conclusion should be a specific statement that includes important findings with a brief discussion of problems, or revisions, or suggestions you may have for improving the circuit. It should directly relate to the objectives of the experiment. For example, if the objective of the experiment is to use the concept of equivalent circuits to simplify series-parallel circuit analysis (as in Experiment 10), the conclusion can refer to the simplified circuit drawings and indicate that these circuits were used to compute the actual voltages and currents in the experiment. Then include a statement comparing the measured and computed results as evidence that the equivalent circuits you developed in the experiment were capable of simplifying the analysis.

The Laboratory Notebook

Your instructor may assign a formal laboratory report or a report may be assigned in the section titled For Further Investigation. A suggested format for formal reports is as follows:

1. Title and date.

2. Purpose: Give a statement of what you intend to determine as a result of the investigation.

3. Equipment and materials: Include a list of equipment model and serial numbers that can allow retracing if a defective or uncalibrated piece of equipment was used.

4. Procedure: Give a description of what you did and what measurements you made.

5. Data: Tabulate raw (unprocessed) data; data may be presented in graph form.

6. Sample calculations: Give the formulas that you applied to the raw data to transform them to processed data.

7. Conclusion: The conclusion is a specific statement supported by the experimental data. It should relate to the objectives for the experiment as described earlier. For example, if the purpose of the experiment is to determine the frequency response of a filter, the conclusion should describe the frequency response or contain a reference to an illustration of the response.

Graphing

A graph is a pictorial representation of data that enables you to see the effect of one variable on another. Graphs are widely used in experimental work to present information because they enable the reader to discern variations in magnitude, slope, and direction between two quantities. In this manual, you will graph data in many experiments. You should be aware of the following terms that are used with graphs:

abscissa: the horizontal or x-axis of a graph. Normally the independent variable is plotted along the abscissa.

dependent variable: a quantity that is influenced by changes in another quantity (the independent variable).

graph: a pictorial representation of a set of data constructed on a set of coordinates that are drawn at right angles to each other. The graph illustrates one variable's effect on another.

independent variable: the quantity that the experimenter can change.

ordinate: the vertical or y-axis of a graph. Normally the dependent variable is plotted along the abscissa.

scale: the value of each division along the x- or y-axis. In a linear scale, each division has equal weight. In a logarithmic scale, each division represents the same percentage change in the variable.

The following steps will guide you in preparing a graph:

Determine the type of scale that will be used. A linear scale is the most frequently used and will be discussed here. Choose a scale factor that enables all of the data to be plotted on the graph without being cramped. The most common scales are 1, 2, 5, or 10 units per division. Start both axes from zero unless the data covers less than half of the length of the coordinate.

Number the major divisions along each axis. Do not number each small division as it will make the graph appear cluttered. Each division must have equal weight. Note: The experimental data is not used to number the divisions.

Label each axis to indicate the quantity being measured and the measurement units. Usually, the measurement units are given in parentheses.

Plot the data points with a small dot with a small circle around each point. If additional sets of data are plotted, use other distinctive symbols (such as triangles) to identify each set.

Draw a smooth line that represents the data trend. It is normal practice to consider data points but to ignore minor variations due to experimental errors. (Exception: calibration curves and other discontinuous data are connected "dot-to-dot.

Title the graph, indicating with the title what the graph represents. The completed graph should be self-explanatory.

Safety in the Laboratory

The experiments in this lab book are designed for low voltages to minimize electric shock hazard; however, never assume that electric circuits are safe. A current of a few milliamps through the body can be lethal. In addition, electronic laboratories often contain other hazards such as chemicals and power tools. For your safety, you should review laboratory safety rules before beginning a course in electronics. In particular, you should

Avoid contact with any voltage source. Turn off power before working on circuits.

Remove watches, jewelry, rings, and so forth before working on circuits—even those circuits with low voltages—as burns can occur.

Know the location of the emergency power-off switch.

Never work alone in the laboratory.

Keep a neat work area and handle tools properly. Wear safety goggles or gloves when required.

Ensure that line cords are in good condition and grounding pins are not missing or bent. Do not defeat the three-wire ground system in order to make "floating" measurements.

Check that transformers and instruments that are plugged into utility lines are properly fused and have no exposed wiring. If you are not certain about procedure, check with your instructor first.

Report any unsafe condition to your instructor.

Be aware of and follow laboratory rules.

Experiments in Digital Fundamentals, 10th Edition by David M. Buchla (z-lib.org)

Introduction to the Student

Circuit Wiring

An important skill needed by electronics technicians is that of transforming circuit drawings into working prototypes. The circuits in this manual can be constructed on solderless protoboards (“breadboards”) available at Radio Shack and other suppliers of electronic equipment. These boards use #22- or #24-gauge solid core wire, which should have 3/8 inch of the insulation stripped from the ends. Protoboard wiring is not difficult, but it is easy to make a wiring error that is time-consuming to correct. Wires should be kept neat and close to the board. Avoid wiring across the top of integrated circuits (ICs) or using wires much longer than necessary. A circuit that looks like a plate of spaghetti is difficult to follow and worse to troubleshoot.

One useful technique to help avoid errors, especially with larger circuits, is to make a wire list. After assigning pin numbers to the ICs, tabulate each wire in the circuit, showing where it is to be connected and leaving a place to check off when it has been installed. Another method is to cross out each wire on the schematic as it is added to the circuit. Remember the power supply and ground connections, because they frequently are left off logic drawings. Finally, it is useful to “daisy-chain,” in the same color, signal wires that are connected to the same electrical point. Daisy-chaining is illustrated in Figure 1-1.

Troubleshooting

When the wiring is completed, test the circuit. If it does not work, turn off the power and recheck the wiring. Wiring, rather than a faulty component, is the more likely cause of an error. Check that the proper power and ground are connected to each IC. If the problem is electrical noise, decoupling capacitors between the power supply and ground may help. Good troubleshooting requires the technician to understand clearly the purpose of the circuit and its normal operation. It can begin at the input and proceed toward the output; or it can begin at the output and proceed toward the input; or it can be done by half-splitting the circuit. Whatever procedure you choose, there is no substitute for understanding how the circuit is supposed to behave and applying your knowledge to the observed conditions in a systematic way.

The Laboratory Notebook

Purpose of a Laboratory Notebook

The laboratory notebook forms a chronologic record of laboratory work in such a manner that it can be reconstructed if necessary. The notebook is a bound and numbered daily record of laboratory work. Data are recorded as they are observed. Each page is dated as it is done and the signature of the person doing the work is added to make the work official; laboratory notebooks may be the basis of patent applications or have other legal purposes. No pages are left blank and no pages may be removed.

General Information

The format of laboratory notebooks may vary; however, certain requirements are basic to all laboratory notebooks. The name of the experimenter, date, and purpose of the experiment are entered at the top of each page. All test equipment should be identified by function, manufacturer, and serial number to facilitate reconstruction of the experiment. Test equipment may be identified on a block diagram or circuit drawing rather than an equipment list. References to any books, articles, or other sources that were used in preparing for the experiment are noted. A brief description of the procedure is necessary. The procedure is not a restatement of the instructions in the experiment book but rather is a concise statement about what was done in the experiment.

Recording of Data

Data taken in an experiment should be directly recorded in tabular form in the notebook. Raw (not processed) data should be recorded. They should not be transcribed from scratch paper. When calculations have been applied to data, a sample calculation should be included to indicate clearly what process has been applied to the raw data. If an error is made, a single line should be drawn through the error with a short explanation.

Graphs

A graph is a visual tool that can quickly convey to the reader the relationship between variables. The eye can discern trends in magnitude or slope more easily from graphs than from tabular data. Graphs are constructed with the dependent variable plotted along the horizontal axis (called the abscissa) and the independent variable plotted along the vertical axis (called the ordinate). A smooth curve can be drawn showing the trend of the data. It is not necessary to connect the data points (except in calibration curves). For data in which one of the variables is related to the other by a power, logarithmic (log) scales in one or both axes may show the relationship of data. Log scales can show data over a large range of values that will not fit on ordinary graph paper. When you have determined the type of scale that best shows the data, select numbers for the scale that are easily read. Do not use the data for the scale; rather, choose numbers that allow the largest data point to fit on the graph. Scales should generally start from zero unless limitations in the data preclude it. Data points on the graph should be shown with a dot in the center of a symbol such as a circle or triangle. The graph should be labeled in a self-explanatory manner. A figure number should be used as a reference in the written explanation.

Schematics and Block Diagrams

Schematics, block diagrams, waveform drawings, and other illustrations are important tools to depict the facts of an experiment. Experiments with circuits need at least a schematic drawing showing the setup and may benefit from other illustrations depending on your purpose. Usually, simple drawings are best; however, sufficient detail must be shown to enable the reader to reconstruct the circuit if necessary. Adequate information should be contained with an illustration to make its purpose clear to the reader.

Results and Conclusion

The section that discusses the results and conclusion is the most important part of your laboratory notebook; it contains the key findings of your experiment. Each experiment should contain a conclusion, which is a specific statement about the important results you obtained. Be careful about sweeping generalizations that are not warranted by the experiment. Before writing a conclusion, it is useful to review the purpose of the experiment. A good conclusion “answers” the purpose of the experiment. For example, if the purpose of the experiment was to determine the frequency response of a filter, the conclusion should describe the frequency response or contain a reference to an illustration of the response. In addition, the conclusion should contain an explanation of difficulties, unusual results, revisions, or any suggestions you may have for improving the circuit.

Suggested Format

From the foregoing discussion, the following format is suggested. This format may be modified as circumstances dictate.

1. Title and date.

2. Purpose: Give a statement of what you intend to determine as a result of the investigation.

3. Equipment and materials: Include equipment model and serial numbers, which can allow retracing if a defective or uncalibrated piece of equipment was used.

4. Procedure: Include a description of what you did and what measurements you made. A reference to the schematic drawing should be included.

5. Data: Tabulate raw (unprocessed) data; data may be presented in graph form.

6. Sample calculations: If you have a number of calculations, give a sample calculation that shows the formulas you applied to the raw data to transform it to processed data. This section may be omitted if calculations are clear from the procedure or are discussed in the results.

7. Results and conclusion: This section is the place to discuss your results, including experimental errors. This section should contain key information about the results and your interpretation of the significance of these results.

Each page of the laboratory notebook should be signed and dated, as previously discussed.

The Technical Report

Effective Writing

The purpose of technical reports is to communicate technical information in a way that is easy for the reader to understand. Effective writing requires that you know your reader’s background. You must be able to put yourself in the reader’s place and anticipate what information you must convey to have the reader understand what you are trying to say. When you are writing experimental results for a person working in your field, such as an engineer, your writing style may contain words or ideas that are unfamiliar to a layperson. If your report is intended for persons outside your field, you will need to provide background information.

Words and Sentences

You will need to either choose words that have clear meaning to a general audience or define every term that does not have a well-established meaning. Keep sentences short and to the point. Short sentences are easiest for the reader to comprehend. Avoid stringing together a series of adjectives or modifiers. For example, the figure caption below contains a jibberish string of modifiers:

Operational amplifier constant current source schematic

By changing the order and adding natural connectors such as of, using, and an, the meaning can be clarified:

Schematic of a constant current source using an operational amplifier

Paragraphs

Paragraphs must contain a unit of thought. Excessively long paragraphs suffer from the same weakness that afflicts overly long sentences. The reader is asked to digest too much material at once, causing comprehension to diminish. Paragraphs should organize your thoughts in a logical format. Look for natural breaks in your ideas. Each paragraph should have one central idea and contribute to the development of the entire report.

Good organization is the key to a well-written report. Outlining in advance will help organize your ideas. The use of headings and subheadings for paragraphs or sections can help steer the reader through the report. Subheadings also prepare the reader for what is ahead and make the report easier to understand.

Figures and Tables

Figures and tables are effective ways to present information. Figures should be kept simple and to the point. Often a graph can make clear the relationship between data. Comparisons of different data drawn on the same graph make the results more obvious to the reader. Figures should be labeled with a figure number and a brief title. Don’t forget to label both axes of graphs.

Data tables are useful for presenting data. Usually, data that are presented in a graph or figure should not also be included in a data table. Data tables should be labeled with a table number and short title. The data table should contain enough information to make its meaning clear: The reader should not have to refer to the text. If the purpose of the table is to compare information, then form the data in columns rather than rows. Column information is easier for people to compare. Table footnotes are a useful method of clarifying some point about the data. Footnotes should appear at the bottom of the table with a key to where the footnote applies. Data should appear throughout your report in consistent units of measurement. Most sciences use the metric system; however, the English system is still sometimes used. The metric system uses derived units, which are cgs (centimeter-gramsecond) or mks (meter-kilogram-second). It is best to use consistent metric units throughout your report or to include a conversion chart.

Reporting numbers using powers of 10 can be a sticky point with reference to tables. Table 1-1 shows four methods of abbreviating numbers in tabular form. The first column is unambiguous as the number is presented in conventional form. This requires more space than if we present the information in scientific notation. In column 2, the same data are shown with a metric prefix used for the unit. In column 3, the power of 10 is shown. Each of the first three columns shows the measurement unit and is not subject to misinterpretation. Column 4, on the other hand, is wrong. In this case the author is trying to tell us what operation was performed on the numbers to obtain the values in the column. This is incorrect because the column heading should contain the unit of measurement for the numbers in the column.

Suggested Format

1. Title: A good title must convey the substance of your report by using key words that provide the reader with enough information to decide whether the report should be investigated further.

2. Contents: Key headings throughout the report are listed with page numbers.

3. Abstract: The abstract is a brief summary of the work, with principal facts and results stated in concentrated form. It is a key factor for a reader to determine if he or she should read further.

4. Introduction: The introduction orients your reader to your report. It should briefly state what you did and give the reader a sense of the purpose of the report. It may tell the reader what to expect and briefly describe the report’s organization.

5. Body of the report: The report can be made clearer to the reader if you use headings and subheadings in your report. The headings and subheadings can be generated from the outline of your report. Figures and tables should be labeled and referenced from the body of the report.

6. Conclusion: The conclusion summarizes important points or results. It may refer to figures or tables previously discussed in the body of the report to add emphasis to significant points. In some cases, the primary reasons for the report are contained within the body and a conclusion is deemed to be unnecessary.

7. References: References are cited to enable the reader to find information used in developing your report or work that supports your report. The reference should include all authors’ names in the order shown in the original document. Use quotation marks around portions of a complete document such as a journal article or a chapter of a book. Books, journals, or other complete documents should be underlined. Finally, list the publisher, city, date, and page numbers.

Experiments in Electronics Fundamentals and Electric Circuits Fundamentals To Accompany Floyd, Electronics Fundamentals and Electric Circuit Fundamentals by David Buchla (z-lib.org)

Introduction to the Student David Buchla

Preparing for Laboratory Work

The purpose of experimental work is to help you gain a better understanding of the principles

of electronics and to give you experience with instruments and methods used by technicians

and electronic engineers. You should begin each experiment with a clear idea of the purpose

of the experiment and the theory behind the experiment. Each experiment requires you to use

electronic instruments to measure various quantities. The measured data are to be recorded,

and you need to interpret the measurements and draw conclusions about your work. The

ability to measure, interpret, and communicate results is basic to electronic work.

Preparation before coming to the laboratory is an important part of experimental work.

You should prepare in advance for every experiment by reading the Reading, Objectives, and

Summary of Theory sections before coming to class. The Summary of Theory is not intended

to replace the theory presented in the text—it is meant only as a short review to jog your

memory of key concepts and to provide some insight to the experiment. You should also look

over the Procedure for the experiment. This prelab preparation will enable you to work

efficiently in the laboratory and enhance the value of the laboratory time.

This laboratory manual is designed to help you measure and record data as efficiently

as possible. Techniques for using instruments are described in many experiments. Data tables

are prepared and properly labeled to facilitate recording. Plots are provided where necessary.

You will need to interpret and discuss the results in the section titled Conclusion and answer

the Evaluation and Review Questions. The Conclusion to an experiment is a concise

statement of your key findings from the experiment. Be careful of generalizations that are not

supported by the data. The conclusion should be a specific statement that includes important

findings with a brief discussion of problems, or revisions, or suggestions you may have for

improving the circuit. It should directly relate to the objectives of the experiment. For

example, if the objective of the experiment is to use the concept of equivalent circuits to

simplify series-parallel circuit analysis (as in Experiment 10), the conclusion can refer to the

simplified circuit drawings and indicate that these circuits were used to compute the actual

voltages and currents in the experiment. Then include a statement comparing the measured

and computed results as evidence that the equivalent circuits you developed in the

experiment were capable of simplifying the analysis.

The Laboratory Notebook

Your instructor may assign a formal laboratory report or a report may be assigned in the

section titled For Further Investigation. A suggested format for formal reports is as follows:

Title and date.

Purpose: Give a statement of what you intend to determine as a result of the

investigation.

Equipment and materials: Include a list of equipment model and serial numbers that

can allow retracing if a defective or uncalibrated piece of equipment was used.

Procedure: Give a description of what you did and what measurements you made.

Data: Tabulate raw (unprocessed) data; data may be presented in graph form.

Sample calculations: Give the formulas that you applied to the raw data to transform

them to processed data.

7. Conclusion: The conclusion is a specific statement supported by the experimental

data. It should relate to the objectives for the experiment as described earlier. For

example, if the purpose of the experiment is to determine the frequency response of a

filter, the conclusion should describe the frequency response or contain a reference to

an illustration of the response.

Graphing

A graph is a pictorial representation of data that enables you to see the effect of one variable

on another. Graphs are widely used in experimental work to present information because they

enable the reader to discern variations in magnitude, slope, and direction between two

quantities. In this manual, you will graph data in many experiments. You should be aware of

the following terms that are used with graphs:

abscissa: the horizontal or x-axis of a graph. Normally the independent variable is plotted

along the abscissa.

dependent variable: a quantity that is influenced by changes in another quantity (the

independent variable).

graph: a pictorial representation of a set of data constructed on a set of coordinates that are

drawn at right angles to each other. The graph illustrates one variable's effect on another.

independent variable: the quantity that the experimenter can change.

ordinate: the vertical or y-axis of a graph. Normally the dependent variable is plotted along

the abscissa.

scale: the value of each division along the x- or y-axis. In a linear scale, each division has

equal weight. In a logarithmic scale, each division represents the same percentage change in

the variable.

The following steps will guide you in preparing a graph:

Determine the type of scale that will be used. A linear scale is the most frequently

used and will be discussed here. Choose a scale factor that enables all of the data to

be plotted on the graph without being cramped. The most common scales are 1, 2, 5,

or 10 units per division. Start both axes from zero unless the data covers less than half

of the length of the coordinate.

Number the major divisions along each axis. Do not number each small division as it

will make the graph appear cluttered. Each division must have equal weight. Note:

The experimental data is not used to number the divisions.

Label each axis to indicate the quantity being measured and the measurement units.

Usually, the measurement units are given in parentheses.

Plot the data points with a small dot with a small circle around each point. If

additional sets of data are plotted, use other distinctive symbols (such as triangles) to

identify each set.

Draw a smooth line that represents the data trend. It is normal practice to consider

data points but to ignore minor variations due to experimental errors. (Exception:

calibration curves and other discontinuous data are connected "dot-to-dot.

Title the graph, indicating with the title what the graph represents. The completed

graph should be self-explanatory.

Safety in the Laboratory

The experiments in this lab book are designed for low voltages to minimize electric shock

hazard; however, never assume that electric circuits are safe. A current of a few milliamps

through the body can be lethal. In addition, electronic laboratories often contain other

hazards such as chemicals and power tools. For your safety, you should review laboratory

safety rules before beginning a course in electronics. In particular, you should

Avoid contact with any voltage source. Turn off power before working on circuits.

Remove watches, jewelry, rings, and so forth before working on circuits—even those

circuits with low voltages—as burns can occur.

Know the location of the emergency power-off switch.

Never work alone in the laboratory.

Keep a neat work area and handle tools properly. Wear safety goggles or gloves when

required.

Ensure that line cords are in good condition and grounding pins are not missing or

bent. Do not defeat the three-wire ground system in order to make "floating" measurements.

Check that transformers and instruments that are plugged into utility lines are properly

fused and have no exposed wiring. If you are not certain about procedure, check with

your instructor first.

Report any unsafe condition to your instructor.

Be aware of and follow laboratory rules.

Experiments in Digital Fundamentals, 10th Edition by David M. Buchla (z-lib.org)

Introduction to the Student

Circuit Wiring

An important skill needed by electronics technicians is that of transforming circuit drawings into working prototypes. The circuits in this manual can be constructed on solderless protoboards (“breadboards”) available at Radio Shack and other suppliers of electronic equipment. These boards use #22- or #24-gauge solid core wire, which should have 3/8 inch of the insulation stripped from the ends. Protoboard wiring is not difficult, but it is easy to make a wiring error that is time-consuming to correct. Wires should be kept neat and close to the board. Avoid wiring across the top of integrated circuits (ICs) or using wires much longer than necessary. A circuit that looks like a plate of spaghetti is difficult to follow and worse to troubleshoot.

One useful technique to help avoid errors, especially with larger circuits, is to make a wire list. After assigning pin numbers to the ICs, tabulate each wire in the circuit, showing where it is to be connected and leaving a place to check off when it has been installed. Another method is to cross out each wire on the schematic as it is added to the circuit. Remember the power supply and ground connections, because they frequently are left off logic drawings. Finally, it is useful to “daisy-chain,” in the same color, signal wires that are connected to the same electrical point. Daisy-chaining is illustrated in Figure 1-1.

Troubleshooting
When the wiring is completed, test the circuit. If it does not work, turn off the power and recheck the wiring. Wiring, rather than a faulty component, is the more likely cause of an error. Check that the proper power and ground are connected to each IC. If the problem is electrical noise, decoupling capacitors between the power supply and ground may help. Good troubleshooting requires the technician to understand clearly the purpose of the circuit and its normal operation. It can begin at the input and proceed toward the output; or it can begin at the output and proceed toward the input; or it can be done by half-splitting the circuit. Whatever procedure you choose, there is no substitute for understanding how the circuit is supposed to behave and applying your knowledge to the observed conditions in a systematic way.

The Laboratory Notebook

Purpose of a Laboratory Notebook

The laboratory notebook forms a chronologic record of laboratory work in such a manner that it can be reconstructed if necessary. The notebook is a bound and numbered daily record of laboratory work. Data are recorded as they are observed. Each page is dated as it is done and the signature of the person doing the work is added to make the work official; laboratory notebooks may be the basis of patent applications or have other legal purposes. No pages are left blank and no pages may be removed.

General Information
The format of laboratory notebooks may vary; however, certain requirements are basic to all laboratory notebooks. The name of the experimenter, date, and purpose of the experiment are entered at the top of each page. All test equipment should be identified by function, manufacturer, and serial number to facilitate reconstruction of the experiment. Test equipment may be identified on a block diagram or circuit drawing rather than an equipment list. References to any books, articles, or other sources that were used in preparing for the experiment are noted. A brief description of the procedure is necessary. The procedure is not a restatement of the instructions in the experiment book but rather is a concise statement about what was done in the experiment.

Recording of Data
Data taken in an experiment should be directly recorded in tabular form in the notebook. Raw (not processed) data should be recorded. They should not be transcribed from scratch paper. When calculations have been applied to data, a sample calculation should be included to indicate clearly what process has been applied to the raw data. If an error is made, a single line should be drawn through the error with a short explanation.

Graphs
A graph is a visual tool that can quickly convey to the reader the relationship between variables. The eye can discern trends in magnitude or slope more easily from graphs than from tabular data. Graphs are constructed with the dependent variable plotted along the horizontal axis (called the abscissa) and the independent variable plotted along the vertical axis (called the ordinate). A smooth curve can be drawn showing the trend of the data. It is not necessary to connect the data points (except in calibration curves). For data in which one of the variables is related to the other by a power, logarithmic (log) scales in one or both axes may show the relationship of data. Log scales can show data over a large range of values that will not fit on ordinary graph paper. When you have determined the type of scale that best shows the data, select numbers for the scale that are easily read. Do not use the data for the scale; rather, choose numbers that allow the largest data point to fit on the graph. Scales should generally start from zero unless limitations in the data preclude it. Data points on the graph should be shown with a dot in the center of a symbol such as a circle or triangle. The graph should be labeled in a self-explanatory manner. A figure number should be used as a reference in the written explanation.

Schematics and Block Diagrams

Schematics, block diagrams, waveform drawings, and other illustrations are important tools to depict the facts of an experiment. Experiments with circuits need at least a schematic drawing showing the setup and may benefit from other illustrations depending on your purpose. Usually, simple drawings are best; however, sufficient detail must be shown to enable the reader to reconstruct the circuit if necessary. Adequate information should be contained with an illustration to make its purpose clear to the reader.

Results and Conclusion
The section that discusses the results and conclusion is the most important part of your laboratory notebook; it contains the key findings of your experiment. Each experiment should contain a conclusion, which is a specific statement about the important results you obtained. Be careful about sweeping generalizations that are not warranted by the experiment. Before writing a conclusion, it is useful to review the purpose of the experiment. A good conclusion “answers” the purpose of the experiment. For example, if the purpose of the experiment was to determine the frequency response of a filter, the conclusion should describe the frequency response or contain a reference to an illustration of the response. In addition, the conclusion should contain an explanation of difficulties, unusual results, revisions, or any suggestions you may have for improving the circuit.

Suggested Format
From the foregoing discussion, the following format is suggested. This format may be modified as circumstances dictate.
1. Title and date.
2. Purpose: Give a statement of what you intend to determine as a result of the investigation.
3. Equipment and materials: Include equipment model and serial numbers, which can allow retracing if a defective or uncalibrated piece of equipment was used.
4. Procedure: Include a description of what you did and what measurements you made. A reference
to the schematic drawing should be included.
5. Data: Tabulate raw (unprocessed) data; data may be presented in graph form.
6. Sample calculations: If you have a number of calculations, give a sample calculation that shows the formulas you applied to the raw data to transform it to processed data. This section may be omitted if calculations are clear from the procedure or are discussed in the results.
7. Results and conclusion: This section is the place to discuss your results, including experimental errors. This section should contain key information about the results and your interpretation of the significance of these results.
Each page of the laboratory notebook should be signed and dated, as previously discussed.

The Technical Report

Effective Writing

The purpose of technical reports is to communicate technical information in a way that is easy for the reader to understand. Effective writing requires that you know your reader’s background. You must be able to put yourself in the reader’s place and anticipate what information you must convey to have the reader understand what you are trying to say. When you are writing experimental results for a person working in your field, such as an engineer, your writing style may contain words or ideas that are unfamiliar to a layperson. If your report is intended for persons outside your field, you will need to provide background information.

Words and Sentences

You will need to either choose words that have clear meaning to a general audience or define every term that does not have a well-established meaning. Keep sentences short and to the point. Short sentences are easiest for the reader to comprehend. Avoid stringing together a series of adjectives or modifiers. For example, the figure caption below contains a jibberish string of modifiers:

Operational amplifier constant current source schematic

By changing the order and adding natural connectors such as of, using, and an, the meaning can be clarified:

Schematic of a constant current source using an operational amplifier

Paragraphs

Paragraphs must contain a unit of thought. Excessively long paragraphs suffer from the same weakness that afflicts overly long sentences. The reader is asked to digest too much material at once, causing comprehension to diminish. Paragraphs should organize your thoughts in a logical format. Look for natural breaks in your ideas. Each paragraph should have one central idea and contribute to the development of the entire report.

Good organization is the key to a well-written report. Outlining in advance will help organize your ideas. The use of headings and subheadings for paragraphs or sections can help steer the reader through the report. Subheadings also prepare the reader for what is ahead and make the report easier to understand.

Figures and Tables
Figures and tables are effective ways to present information.
Figures should be kept simple and to the point. Often a graph can make clear the relationship between data. Comparisons of different data drawn on the same graph make the results more obvious to the reader. Figures should be labeled with a figure number and a brief title. Don’t forget to label both axes of graphs.

Data tables are useful for presenting data.
Usually, data that are presented in a graph or figure should not also be included in a data table. Data tables should be labeled with a table number and short title. The data table should contain enough information to make its meaning clear: The reader should not have to refer to the text. If the purpose of the table is to compare information, then form the data in columns rather than rows. Column information is easier for people to compare. Table footnotes are a useful method of clarifying some point about the data. Footnotes should appear at the bottom of the table with a key to where the footnote applies. Data should appear throughout your report in consistent units of measurement. Most sciences use the metric system; however, the English system is still sometimes used. The metric system uses derived units, which are cgs (centimeter-gramsecond) or mks (meter-kilogram-second). It is best to use consistent metric units throughout your report or to include a conversion chart.

Reporting numbers using powers of 10 can be a sticky point with reference to tables. Table 1-1 shows four methods of abbreviating numbers in tabular form. The first column is unambiguous as the number is presented in conventional form. This requires more space than if we present the information in scientific notation. In column 2, the same data are shown with a metric prefix used for the unit. In column 3, the power of 10 is shown. Each of the first three columns shows the measurement unit and is not subject to misinterpretation. Column 4, on the other hand, is wrong. In this case the author is trying to tell us what operation was performed on the numbers to obtain the values in the column. This is incorrect because the column heading should contain the unit of measurement for the numbers in the column.

Suggested Format

1. Title: A good title must convey the substance of your report by using key words that provide the reader with enough information to decide whether the report should be investigated further.

2. Contents: Key headings throughout the report are listed with page numbers.

3. Abstract: The abstract is a brief summary of the work, with principal facts and results stated in concentrated form. It is a key factor for a reader to determine if he or she should read further.

4. Introduction: The introduction orients your reader to your report. It should briefly state what you did and give the reader a sense of the purpose of the report. It may tell the reader what to expect and briefly describe the report’s organization.
5. Body of the report: The report can be made clearer to the reader if you use headings and subheadings in your report. The headings and subheadings can be generated from the outline of your report. Figures and tables should be labeled and referenced from the body of the report.
6. Conclusion: The conclusion summarizes important points or results. It may refer to figures or tables previously discussed in the body of the report to add emphasis to significant points. In some cases, the primary reasons for the report are contained within the body and a conclusion is deemed to be unnecessary.
7. References: References are cited to enable the reader to find information used in developing your report or work that supports your report. The reference should include all authors’ names in the order shown in the original document. Use quotation marks around portions of a complete document such as a journal article or a chapter of a book. Books, journals, or other complete documents should be underlined. Finally, list the publisher, city, date, and page numbers.