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Views Downloads 64 File size 26MB. Technical Information 1. V AIR. Counters 8-bit counter; Cascading; Load from keypad; Programmable divide-by-n counter; Period meter; Capacitance meter Lab Lab The students this student manual for the art of electronics download might suit These notes arose out of a course at Harvard; they define what we try to teach in that busy term. The course does less than all of Horowitz and Hill, of course.
We treat chaptersomitting Chapter 7, on Precision Circuits Even this selection includes more information than we expect students to absorb fully on a first pass through the book. This Manual tries to guide students to the most important material. The typical student that we see-if there really is a typical student-is an undergraduate majoring in Physics, and wanting to learn enough electronics to let him or her do useful work in a laboratory. But we do not assume such background in these notes.
Students very different from that typical student thrive in our course. Graduate students in the sciences appear regularly; during the summer we see many high school students, and some of these do brilliantly; now and then a professor of Physics takes the course and they do all right, too!
In the 'extension' version of the course, we see lots of programmers who want to know what's going on in their machines, and we see people who just happen to be curious about electronics. That curiosity, in fact, is the only prerequisite for this course, and suggests the only good rule to define who will enjoy it. Someone looking for an engineering course will find our treatment oddly informal, but a person eager to learn how to design useful circuits will like this course.
Laboratory Exercises The laboratory exercises build upon a set of labs that were set out in the edition of the Student manual for the art of electronics download Manual, by Horowitz and Robinson. The new exercises replace all of the original digital labs and substantially revise the analog labs on PET's and oscillators. In the digital section we have switched over from LSTTL to HCMOS, but the major change has been the enlarged student manual for the art of electronics download given to the microprocessor labs, and the shift from the Z80 processor programmed rather laboriously via a DIP switch to a processor programmed through a keypad.
A complete schematic is included. See Lab Complete student manual for the art of electronics download units are available through the authors. See Parts list. We have held to our intention that students should build their computer from the chip level, and that they should student manual for the art of electronics download be handed a ROM cleverly programmed by someone else. The digital half of the course now centers student manual for the art of electronics download the microcomputer: we meet simpler digital devices-gates, flip-flops, counters, memory-partly because we want to be able to build small digital circuits, but also partly in order to understand the full microcomputer circuit.
The A-D conversion experiments have been expanded to include the effects of sampling-rate and of filters applied to input and output. The notes explain at length. They do this at a student manual for the art of electronics download more basic than the Text's, and they provide explanations in a step-by-step style that the Text cannot afford, given its need to cover far more material. A suggestion: how to use the notes Here's a proposal; you will, of course, find your own way to use Text, Notes and all the other course materials.
But here is one way to begin. It will include some material that is subtler than what we expect you to pick up in a продолжить course. You may want to hear some points restated in another way, or you may want to see an example worked.
Primed with this specific sort of curiosity, you might thenLook at the day's Notes and Lab: scan, first, to see which circuits and which points are selected. Read the Notes on any points that puzzled you; if you still are student manual for the art of electronics download, return to the Text for a second look at the topics you now know are most important.
Skip topics in the Notes that перейти на источник understand already. The Notes are meant to help you, not to burden you with additional reading: if you have read статья windows 10 2020 build free замечательная understood the Text's discussion of a topic, you will miss nothing by omitting the corresponding section in the Student manual for the art of electronics download.
Try the day's worked example, at least in your head. If it looks easy, you may want to skip it. If it looks hard, probably you should try to do your own solution. If you find yourself heading into a lot of work-especially any involved calculations-probably you are doing unnecessary labor, and it is time to peek at our solution. We hope to teach you an approach to problems of circuit design, not just a set of particular rules.
If there is a laborious way and a quick way to reach a good design, we want to push you firmly toward the quick way. We expect that some of these notes will strike you as babyish, some as excessively dense: your reaction naturally reflects the uneven experience you have had with the topics the Text and Manual treat. Some of you are sophisticated programmers, and will sail through the assembly-language programming near the course's end; others will find it heavy going.
The course out of which this Manual grew-and, earlier, the Text as well-has a reputation as fun, and not difficult in one sense, but difficult in another: the concepts are straightforward; abstractions are few. But we do pass a lot of information to our students in a short time; we do expect them to achieve literacy rather fast.
This course is a lot like an introductory language course, and we hope to teach by the method sometimes called immersion. It is the laboratory exercises that do the best teaching; we hope the Text and this Manual will help to make those exercises instructive. Why our figures and text look the way they do You will discover very quickly that this manual is informal in language and layout.
The figures all are hand-drawn. They are done by hand partly because we like the look of handdrawn figures when they are done right; not all our figures are prettyand partly because we want to encourage students нажмите для продолжения do their own free-hand drafting of schematics. In some cases we did draft drawings on a computer, then основываясь на этих данных the final versions by hand! The text was produced as camera-ready copy, put out by an ordinary PC word processor.
So-as writers used to say, long ago-dear reader, look with sympathy, if you can, when you find a typo, or a figure drawn amiss. Don't blame the publisher for corporate sloth. Picture, instead, two fellows hunched over their keyboard and drawing board, late at night and beginning to get drowsy. Who helped especially with this book Two teaching fellows gave us good advice on uncounted occasions: Shahn Majid, a mathematical Physicist who taught with us for years in the Harvard College course, and Steve Morss, a digital engineer who once took the course and then returned to teach.
Steve детальнее на этой странице would linger late into the night helping to try out a new circuit or analyze an old one. Both of these two could perfectly well have taught the course, and chose nevertheless to linger-Bodhissattva-like-giving their expert help in this quieter way.
A pair of our former students, Jeff Hobson and Wei-Jing Zhu, helped us first by drawing figures-and then gradually turned into this book's godparents, helping in all sorts of ways. Often they would arrive in the evening, at the end of a long day's work, and then would labor to help us organize, check, re-check-and also to make judgments on how to make our points clearly.
Often the end of the workday was defined by the departure of the last bus, at in the morning. Their devotion to the project was invaluable, and touching. Finally, Debbie Mills deserves thanks for putting up with her husband Tom's strange, long hours, student manual for the art of electronics download then, toward the end, doing much more: providing essential help in organizing, checking, and correcting the growing stacks of printouts and drawings.
July 1 CHAPTER I Overview The title of this first chapter, "Foundations," describes its place pretty well: here you will learn techniques that will underlie circuitry that later produces impressive results. But очень windows 10 gaming problems free download удачи circuit elements that this chapter treats-passive devices-appear over and over in later active circuits.
So, if a student happens to tell us, 'I'm going to be away on the day взято отсюда doing Lab 2,' we tell him he will have to make up the lab somehow: that the second lab, on RC circuits, is the most important in the course. If you do not use that lab to cement your understanding of RC circuits-especially filters-then you will be haunted by muddled thinking for at least the remainder of analog part of the course. Resistors will give you no trouble; diodes will seem simple enough, at least in the view that we settle for: they are one-way conductors.
Capacitors and inductors behave more strangely. We will see very few circuits that use inductors, but a great many that use capacitors. You are likely to need a good deal of practice before you get comfortable with the central facts of capacitors' behavior-easy to state, hard to get an intuitive grip on: they pass AC, block DC, and sometimes cause large phase shifts.
We should also restate a word of reassurance offered by the Text p. This is the place in the Text and course where the squeamish usually begin to wonder if they ought to retreat to some slower-paced treatment of the subject.
Do not give up at this point; hang on until you have seen transistors, at least. The mathematical arguments of 1. To the contrary, one of the most striking qualities of this Text is its cheerful evasion of complexity whenever a simpler account can carry you to a good design.
The treatment of transistors offers a good example, and you ought to stay with the course long enough to see that: the transistor chapter is difficult, but wonderfully simpler than most other treatments of the subject.
You will begin designing useful transistor circuits on your first day with the subject. It is also in the first three labs that you will get student manual for the art of electronics download to the lab instruments-and especially to the most important of these, the oscilloscope. It is a complex machine; only practice will teach you to use it well.
Do not make the common mistake of thinking that the person next to you who is turning knobs so confidently, flipping switches and adjusting trigger level-all on the first day of the course-is smarter than you are.
No, that person has done it before. In two weeks, you too will vegas free 13 free sony transitions pro making the scope do your bidding-assuming that you don't leave the work to that person next to you-who knew it all from the beginning. The images on the scope screen make silent and invisible events visible, though strangely abstracted as well; these scope traces will become your mental images of what happens in your circuits.
The scope student manual for the art of electronics download serve as a time microscope that will let you see events that last a handful of nanoseconds: the length of time light takes to get from you to the person sitting a little way down the lab bench. You may Вам upgrade vmware fusion pro 10 to 11 free download прострели find yourself reacting emotionally to shapes 2 Ch. Anticipating some of these experiences, and to get you in the mood to enjoy the coming weeks in which small student manual for the art of electronics download will paint their self-portraits on your screen, we offer you a view of some scope traces that never quite occurred, and that nevertheless seem just about right: just what a scope would show if it could.
This drawing has been posted on one of our doors for years, now, and student manual for the art of electronics download who happen by pause, peer, hesitate--evidently working a bit to put a mental frame around these not-quite-possible pictures; sometimes they ask if these are scope traces. They are not, of course; the leap beyond what a scope can show was the artist's: Saul Steinberg's.
Graciously, he has allowed us to show his drawing here. We hope you enjoy it. Perhaps it will help you to look on your less exotic scope displays with a little of the respect and wonder with which we have to look on the traces below. Small plane t t. Sounds simple, and it is.
We student manual for the art of electronics download try to point out quick ways to handle these familiar circuit elements. We will concentrate on one circuit fragment, the voltage divider. Preliminary: What is "the art of electronics?
❿Student manual for the art of electronics download
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Report this Document. Flag for inappropriate content. Download now. Hayes, P For Later. Jump to Page. Student manual for the art of electronics download inside document. Worked example: Differential amplifier. Lab 6: Transistors III Wrap-up Ch. Worked exampl follower Schmitt trigger. Wrap-up Chs. Jargon and terms. Worked example: state machines, Lab Memory; State Machines. Wrap-up Ch, 8: Electrlnics. DG analog switch. Lab 2.
Lab 3. Lab 4. Lab 5. Lab 6. Lab 7. Lab 9. Lab The students this course might suit These notes arose out of a course at Harvard; they define what we try to teach in that busy term. The course does less than all of Horowitz and Hill, of course. We treat chaptersomitting Chapter 7, on Precision Circuits Even this selection includes server 2016 datacenter 64-bit (portuguese-brazil) free download information than we expect students to absorb fully on a first pass through the book.
This Manual tries to windows server 2012 adk download students to the most important material. The typical student that we see—if there really is a typical student—is an undergraduate majoring in Physics, and wanting to learn enough electronics to let him or her do useful work in a продолжить. But we do not assume such background in these notes. Students very different from that eownload student thrive in our course. Graduate students in the student manual for the art of electronics download appear regularly; during the summer we see many high school students, and some of these do brilliantly; now and then a professor of Physics takes the course and they do all right, too!
That curiosity, in fact, is узнать больше only prerequisite for manusl course, and suggests the only good rule to define who will enjoy it. Someone looking for an engineering course will find our treatment oddly informal, but a person eager to learn how to design useful circuits will like this course.
Laboratory Exercises The laboratory exercises build upon a set of labs that were set out in the edition of the Laboratory Manual, by Horowitz and Robinson.
In the digital section we have switched over from Student manual for the art of electronics download to HCMOS, but the major change has been the enlarged role given to the microprocessor labs, and the shift from the Z80 processor programmed rather laboriously via a DIP student manual for the art of electronics download to a processor programmed through a keypad.
A complete schematic is included. See Lab Complete keypad units are available through the authors. See Parts list. We have held to our intention that посмотреть больше should build their computer from the chip level, and that they should not be handed a ROM cleverly programmed by someone else.
The digital half of the course now centers on the microcomputer: we meet simpler digital devices—gates, flip-flops, counters, memory—partly because we want to be able to build small digital circuits, but also partly in order to understand student manual for the art of electronics download full student manual for the art of electronics download circuit.
The A-D conversion experiments have been expanded to include the effects foe sampling-rate and of filters applied to input and output. Notes The notes that introduce each lab respond to two needs that students often voice: The notes select a few points from the much broader coverage of the Text; those selected points are, of course, those elcetronics we think most important to downolad student meeting practical electronics for the first time.
But here is one way to begin. It will include по ссылке material that is subtler than what we expect you to pick up in a first course. You may want to hear some напугать windows 10 free upgrade for customers who use assistive technologies cnet free download Вам restated in another downloda, or you may want to see an example worked. Read the Notes on any points that puzzled you; if you still are puzzled, return to the Text for a second look at the topics you now know are most important.
If it looks easy, you may want to skip it. If it looks hard, probably you should try to do your own solution. If you find yourself heading into a lot of work—especially any involved calculations—probably you are doing unnecessary labor, and it is time to peek at our solution. We hope to teach you an approach to problems of circuit design, not just a set of particular rules. If there is a laborious way and a quick way to reach a good design, we want to push you firmly toward the quick way.
We expect that some of these notes will strike you as babyish, some as excessively dense: your reaction naturally reflects the uneven experience you have had with the topics the Text and Manual treat. The course out of which this Manual stuednt, earlier, the Text as well—has student manual for the art of electronics download reputation manhal fun, and not difficult in one sense, but difficult in another: the concepts are straightforward; abstractions are few.
But we do pass a lot of information to our students in a short time; we do expect them to achieve literacy rather fast. This course is a lot like an introductory language course, manuaal we hope to teach by the method sometimes called immersion. It is the laboratory exercises that do the best teaching; we hope at Text and this Manual will help to make those exercises instructive. The figures all are hand-drawn. In some cases we did draft drawings on a computer, then drew the final versions by hand!
The text was produced as camera-ready copy, put out by an ordinary PC word processor. So—as writers used to say, long ago—dear reader, look with sympathy, if student manual for the art of electronics download can, when you find a typo, or a figure drawn amiss. Picture, instead, two fellows hunched over their keyboard and drawing board, late at night and beginning to get drowsy.
Who helped especially with student manual for the art of electronics download book Two teaching fellows gave us good advice on uncounted slectronics Shahn Majid, a mathematical Physicist who taught with us for years in the Harvard College course, and Steve Morss, a digital engineer who once took the course and then returned to teach. Steve often would linger late into the night helping to try out a new circuit or analyze an old one.
Both of these two could perfectly well have taught the course, and chose nevertheless to linger—Bodhissattva-like—giving their expert help in this quieter way. Often the end of the workday was defined by the departure of the last bus, at in the morning. Their devotion to the project was invaluable, and touching.
But the circuit elements that this chapter treats—passive devices—appear over and источник in later active circuits. If you do not use that lab to cement your understanding of RC circuits—especially filters—then you will be haunted by muddled thinking for at least the remainder of analog part of the course. Resistors will give you no trouble; diodes will /27001.txt simple enough, at least in the view that we settle for: they are one-way conductors.
Capacitors and inductors eleectronics more strangely. We should also restate a word of reassurance offered by the Text p. This is the place in the Text and course where the squeamish usually begin to wonder if they ought to retreat to some slower-paced treatment of the subject. Do not give up at this point; hang on until you have seen transistors, at least.
The mathematical arguments of 1. To the contrary, one of the most striking qualities of this Text is its cheerful evasion of читать статью whenever a simpler account can carry you to a good design. The treatment of transistors offers a good example, and you ought to stay with the course long enough to see that: the transistor chapter is difficult, but wonderfully simpler than most other treatments of the subject.
❿Student Manual for The Art of Electronics - Student manual for the art of electronics download
We hope you enjoy it. Perhaps it will help you to look on your less exotic scope displays with a little of the respect and wonder with which we have to look on the traces below.
Sounds simple, and it is. We will try to point out quick ways to handle these familiar circuit elements. We will concentrate on one circuit fragment, the voltage divider. With their help you will be able to leave the calculator-bound novice engineer in the dust! Two Laws Text sec. Nevertheless, we rarely will mention Kirchhoff again. What are these?
As the text says, Crudely speaking, the name of the game is to make and use gadgets that have interesting and useful J vs V characteristics. This is kind of boring. First, some labor-saving tricks. Bond, Principles of Electronic Circuits So we proceed immediately to some tricks that let you do most work in your head. Text sec. If you have to work to hard to get the answer, you may find yourself simply not making the estimate.
So, if two parallel resistors differ by a factor of ten, then we can ignore the larger of the two. Parallel resistances: shortcuts Small R large R Ina parallel circuit, a resistor much smaller than others dominates.
One can calculate V,,, in several ways. We will try to push you toward the way that makes it easy to get an answer in your head. Three ways: 1. Calculate the current through the series resistance; use that to calculate the voltage in the lower leg of the divider. Rely on the fact that J is constant in top and bottom, but do that implicitly. Say to yourself in words how the divider works: something like, Since the currents in top and bottom are equal, the voltage drops are proportional to the resistances later, impedances—a more general notion that covers devices other than resistors.
So, in this case, where the lower R makes up half the total resistance, it also will show half the total voltage. Is this no fair? Again there is more than one way to make the new calculation—but one way is tidier than the other. Two possible methods: 1. Tedious Method: Text exercise 1. Evidently, the DVM is a better voltmeter, at least in its R;,—as well as much easier to use. It turns out to be ambiguous. We know that the ground symbol means, in any event, that the bottom ends of the two resistors are electrically joined.
Does it matter whether that point is also tied to the pretty planet we live on? It turns out that it does not. To some extent, the load changes the output. We need to be able to predict and control this change. To do that, we need to understand, first, the characteristic we call Rj, this rarely troubles anyone and, second, the one we have called Rrpevenin this one takes longer to get used to. We start with a goal: Design goal: When circuit A drives circuit B: arrange things so that B loads A lightly enough to cause only insignificant attenuation of the signal.
You know the answer, but confirming it would let you check your understanding of our rule of thumb and its effects. Effects of instrument imperfections, in first lab L 3. Thevenin models 4. Rin Rou 5. What shunt resistance is needed to convert it to a amp meter?
What series resistance will convert it to a volt meter? This exercise gives you a useful insight into the instrument, of course, but it also will give you some practice in judging when to use approximations: how precise to make your calculations, to say this another way. The remaining current must bypass the movement; but the current through the movement must remain proportional to the whole current. Well, what else do we know? We know the resistance of the meter movement.
If you're fresh from a set of Physics courses, you may be inclined toward the first answer. In this setting, it is not. It is a very silly answer. That resistor specification claims to be good to a few parts in a million.
If that were possible at all, it would be a preposterous goal in an instrument that makes a needle move so we can squint at it. In short, the problem is very easy if we have the good sense to let it be easy. Voltmeter Here we want to arrange things so that 10V applied to the circuit causes a full-scale deflection of the movement.
Thinking in volzage terms probably helps one to see that most of the 10V must be dropped across some element we are to add, since only 0. There are two equivalent ways to answer: 1, The resistance must drop 9. The meter movement looks like Sk, we were told; so we need to add the difference, kQ. The difference is 2. Assume that you are applying 20 volts, and that you can find a meter setting that lets you get full-scale deflection in the current meter.
Same question, but concerning current measurement error, if the voltmeter probe is moved to connect directly to the top of the resistor, for the same resistor values. Assume the DVM has an input resistance of 20 Mohms. The error we get results from the voltage drop across the current meter; but we know what that drop is, from problem 1.
So, the resistor values do not matter. Our voltage readings always are high by a quarter volt, if we can set the current meter to give full-scale deflection.
The value of the resistor being measured does not matter. When the DVM reads 20V, the true voltage at the top of the resistor is Our voltage reading is high by 0. Errors in Current readings If we move the DVM to the top of the resistor, then the voltage reading becomes correct: we are measuring what we meant to measure. But now the current meter is reading a little high: it measures not only the resistor current but also the DVM current, which flows parallel to the current in R.
The size of this error depends directly on the size of R we are measuring. TER is then the current error is minute: 1 part in , 0. IfR is2MQ then the error is large: 1 part in ten. Well, this is our first encounter with the concept we like to call Electronic Justice, or the principle that The Greedy Will Be Punished. So, if you set the DVM current range so that your reading looks like.
If you are able to choose a setting that makes the same current look like 0. The leftmost circuit is most easily done by temporarily redefining ground. This example is not meant to make you give up approximations.
In Chapter 2 you will learn to design these things—and you will discover that some devices just do behave like current sources without being coaxed into it: transistors behave this way—both bipolar and FET.
Figure X1. But when we say that are we answering the right question? If not, why was it constructed? But that something else should show its own R;, high enough so that it does not appreciably alter the result you got when you ignored the load. To put this concisely, you might say simply that we assume an ideal load: a load with infinite input impedance. The difficulty, again, is that we need to make some assumption about what is on the far side of the divider if we are to determine R, Racenee: out" Zero a oe Figure X1.
What resistance would the meter present when set to the 10 volt scale? We start, as usual, by trying to reduce the circuit to familiar form. The Thevenin model does that for us.
Additional Exercises 1,2. A preliminary note on procedure The principal challenge here is simply to get used to the breadboard and the way to connect instruments to it. Try to build your circuit on the breadboard, not in the air.
Novices often begin by suspending a resistor between the jaws of alligator clips that run to power supply and meters. Try to do better: plug the resistor into the plastic breadboard strip. Bring power supply and meters to the breadboard through jacks banana jacks, if your breadboard has them ; then plug a wire into the breadboard so as to join resistor, for example, to banana jack.
When you reach circuits that include negative supply, place that on a bus strip below the ground bus. Such color coding helps a little now, a lot later, when you begin to lay out more complicated digital circuits.
Therefore you usually have to break the circuit to measure a current. Measure a few values of V and I for the 20k resistor note: you may well find no 20k resistor in your kit. Next try a 10k resistor instead, and sketch the two curves that these resistors define on a plot of I vs V. Fair enough. Does that matter? How can you fix the circuit so the voltmeter measures what you want? Can you summarize by saying what an ideal voltmeter or ammeter should do to the circuit under test?
A Quantitative View How large is each error, given a 20k resistor. Which of the two alternative hookups is preferable, therefore? Would you have reached the same conclusion if the resistor had been 20MQ? You will find this question pursued in one of the Worked Examples. Do not exceed 6,5 volts! Again you need only a few readings. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks.
Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. Explore Documents. Uploaded by MFawadBaig. Did you find this document useful? Is this content inappropriate? Report this Document. Flag for inappropriate content. Download now. You will soon learn a gentler way to get the same information.
On paper, if you are given the circuit diagram the fastest way to get Rrh for a divider is always to take the parallel resistance of the several resistances that make up the divider again assuming Rsource is ideal: zero Q. Oscilloscope We'll be using the oscilloscope "scope" in virtually every lab from now on.
If you run out of time today, you can learn to use the scope while doing the experiments of Lab 2. You will find Lab 2 easier, however, if today you can devote perhaps 20 minutes to meeting the scope.
If both instruments seem to present you with a bewildering array of switches and knobs, don't blame yourself. These front-panels just are complicated. You will need several lab sessions to get fully used to them-and at term's end you may still not know all: it may be a long time before you find any occasion for use of the holdoff control, for example, or of single-shot triggering, if your scope offers this. This controls "volts! If you don't do this, you can't trust any reading you take!
Don't feel dumb if you have a hard time getting the scope to trigger properly. Triggering is by far the subtlest part of scope operation. When you think you have triggering under control, invite your partner to prove to you that you don't: have your partner randomize some of the scope controls, then see if you can regain a sensible display don't overdo it here!
Beware the tempting so-called "normal" settings usually labeled "NORM". They rarely help, and instead cause much misery when misapplied. Think of "normal" here as short for abnormal!
Save it for the rare occasion when you know you need it. At first you may be inclined to despair, saying "Risetime? The square wave rises instantaneously.
A suggestion on triggering: It's a good idea to watch the edge that triggers the scope, rather than trigger on one event and watch another. If you watch the trigger event, you will find that you can sweep the scope fast without losing the display off the right side of the screen.
Look at this on one channel while you watch a triangle or square wave on the other scope channel. Triggering on a well-defined point in a waveform, such as peak or trough, is especially useful when you become interested in measuring a difference in phase between two waveforms; this you will do several times in the next lab. We won't ask you to use this signal yet; not until Lab 3 do we explain how a scope probe works, and how you "calibrate" it with this signaL For now, just note that this signal is available to you.
Postpone using scope probes until you understand what is within one of these gadgets. A "lOX" scope probe is not just a piece of coaxial cable. Eschew this plausible error. The AC setting on the scope puts a capacitor in series with the scope input, and this can produce startling distortions of waveforms if you forget it is there.
See what a 50 Hz square wave looks like on AC, if you need convincing. Furthermore, the AC setting washes away DC information, as you have seen: it hides from you the fact that a sine wave is sitting on a DC offset, for example.
You don't want to wash away information except when you choose to do so knowingly and purposefully. Once in a while you will want to look at a little sine with its DC level stripped away; but always you will want to know that this DC information has been made invisible.
Set the function generator to some frequency in the middle of its range, then try to make an accurate frequency measurement with the scope. Directly, you are obliged to measure period, of course, not frequency. You will do this operation hundreds of times during this course.
Soon you will be good at it. Trust the scope period readings; distrust the function generator frequency markings; these are useful only for very approximate guidance, on ordinary function generators. Try looking at pulses, say 1!
AC Voltage Divider First spend a minute thinking about the following question: How would the analysis of the voltage divider be affected by an input voltage that changes with time i. Now hook up the voltage divider from lab exercise , above, and see what it does to a 1kHz sine wave use function generator and scope , comparing input and output signals.
If this question seems silly to you, you know either too much or too little. Capacitors let us build circuits that "remember" their recent history. That ability allows us to make timing circuits circuits that let this happen a predetermined time after that occurs ; the most important of such circuits are oscillators-circuits that do this timing operation over and over, endlessly, in order to set the frequency of an output waveform.
The capacitor's memory also lets us make circuits that respond mostly to changes differentiators or mostly to averages integrators , and-by far the most important-circuits that favor one frequency range over another filters. All of these circuit fragments will be useful within later, more complicated circuits. The filters, above all others, will be with us constantly as we meet other analog circuits. They are nearly as ubiquitous as the resistive- voltage divider that we met in the first class.
More often, capacitors achieve large area thus large capacitance by doing something tricky, such as putting the dielectric between two thin layers of metal foil, then rolling the whole thing up like a roll of paper towel mylar capacitors are built this way.
Text sec. V , and Vis the voltage across the cap. It is a Physicist's way of describing how a cap behaves, and rarely will we use it again. C is constant with time; I is defined as the rate at which charge flows. This equation isn't hard to grasp: it says 'The bigger the current, the faster the cap's voltage changes.
If you fill the tub through a thin straw small I , the water level-V-will rise slowly; if you fill or drain through a fire hose big I the tub will fill "charge" or drain "discharge" quickly. A tub of large diameter large capacitor takes longer to fill or drain than a small tub. Selfevident, isn't it? Time-domain Description Text sec. An easy case: constant I Text sec. Much more common is the next case. The cap behaves a lot like the hare in Xeno's paradox: remember him?
Xeno teased his fellow-Athenians by asking a question something like this: 'If a hare keeps going halfway to the wall, then again halfway to the wall, does he ever get there? But it will come as close as you want.
F give time-constant in seconds kQ and j.! F give time-constant in milliseconds In the case above, RC is the product of lk and lj.! F: 1 ms. Figure N2. But the circuit is pretty evidently useless. It gives us no way to measure that current. If we could devise a way to measure the current, we would have a differentiator.
Here's our earlier proposal, again. Does it work? The same reasons prevail, but here they are more urgent: if we don't follow this rule, not only will signals get attenuated; frequency response also is likely to be altered. But to enforce our rule of thumb, we need to know Zin and Zout for the filters. At first glance, the problem looks nasty. What is Zout for the low-pass filter, for example?
A novice would give you an answer that's much more complicated than necessary. We cheerfully sidestep this hard work, by considering only worst case values.
We ask, 'How bad can things get? We ask, 'How bad can Zin get? That is not so. You need an intuitive sense of when phase shifting occurs, and of roughly its magnitude. You rarely will need to calculate the amount of shift. Here is a start: a rough account of phase shift in RC circuits: If the amplitude out is close to amplitude in, you will see little or no phase shift. CJ'T 0. B Figure N2. Have we merely restated our earlier proposition? It almost seems so. Phasor Diagrams These diagrams let you compare phase and amplitude of input and output of circuits that shift phases circuits including C's and L's.
They make the performance graphic, and allow you to get approximate results by use of geometry rather than by explicit manipulation of complex quantities. This plot is known by the extra-frightening name, "complex plane" with nasty overtones, to the untrained ear, of 'too-complicatedfor-you plane'! But don't lose heart. It's all very easy to understand and use.
Even better, you don't need to understand phasors, if you don't want to. We use them rarely in the course, and always could use direct manipulation of the complex quantities instead. Phasors are meant to make you feel better. If they don't, forget them. This gives Vout I Vin of about 1.
Design a current source to replace! We can minimize voltage offset "" VGs Such a device is as almost as easy to use as a resistor why.. FET manufacturers, too, have noticed how handy a device a 2-terminal current source is, and they sell them.
These current sources are sorted by loss; the ' passes about 0. First, try the device in the test circuit you used with the 2N just above. Does this "diode" perform as well as the circuit you built with the '? Would you expect it to? Now, to get a feel for how easy it is to design nifty things with this device, try the circuit below-which at a glance may look foolish.
Here, incidentally, we are exploiting a fact that ordinarily alarms us: a JFET's gate conducts if we forward-bias the gate with respect to either source or drain. Drive the circuit with a 1kHz square wave of about 5 volts' amplitude.
Center the input waveform on zero volts, and note whether the output is centered. If it is not, why is it not? If it is off-center, what stops it from sailing farther off-center? Now gradually lower the input amplitude until you notice distortion in the output curvature, near the points. Why does this occur? By how much does the gain differ from unity.
From this single observation-the follower's attenuation-you can infer gm: the FET's transconductance at this 10 qwescent. Having measured Vr at the start of today's lab, you can see where you must be on the PET's curve. How close is your estimate of gm, so derived, to the value of gm that you observe?
How does the variation of gm compare with the variation of "gm" that you saw for a bipolar transistor, back in the lab where you saw distortion in the common-emitter amplifier exercise Confirm that this follower performs much better than the simpler circuit.
Attempt to measure the input impedance. Measure the DC offset. What accounts for the non-zero offset? Mismatch of FETs or of resistors? What easy circuit changes would let you find out, if you are in doubt? The six-lead package is most easily inserted into the breadboard as two rows of three straddling the central median.
The specified maximum offset for these transistors is 25mV. Is the offset of your circuit as low as that? If not, why not? The case below comes closer to fitting the electronic sense of negative feedback.
In op amp terms not Hollywood's , who's playing what role? He nee. In electronics the truth is usually just the opposite. Feedback in electronics Generally speaking, negative feedback in electronics is wonderful stuff; positive feedback is nasty. Nevertheless the phrase means in electronics fundamentally what it should be used to mean in everyday speech.
Open-loop vsfeedback circuits Nearly all our circuits, so far, have operated open-loop--with some exceptions noted below. You may have gotten used to designing amplifiers to run open-loop we will cure you of that ; you would not consider driving a car open loop we hope , and you probably know that it is almost impossible even to speak intelligibly open-loop.
Examples of Feedback without Op Amps We know that feedback is not new to you, not only because you may have a pretty good idea of the notion from ordinary usage, but also because you have seen feedback at work in parts of some transistor circuits: LabS: ,, out Figure N8. Op amps have enormous gain that is, their openloop gain is enormous: the chip itself, used without feedback, would show huge gain: z, at DC, for the LF, the chip you will use in most of our labs.
As Black suggests, op amp circuits throw away most of that gain, in order to improve circuit performance. The golden rules below are approximations, but good ones : Text sec. The output attempts to do whatever is necessary to make the voltage difference between the two inputs zero. The inputs draw no current. These simple rules will let you analyze a heap of clever circuits. Applications Two Amplifiers Text sec.
Golden Rule 1 should settle that. Approximately what is Rin for the non-inverting amp? Golden Rule 2 should settle that.
The inverting amp's inverting terminal the one marked"-" often is called "virtual ground. Why ground? Why "virtual"? This point, often called by the suggestive name "summing junction," turns out to be useful in several important circuits.
It warns a careful reader that the person designing op amp circuits retains an obligation to use his head: apparently there are circuits in which the op amp will be unable to deliver the desired result: it will attempt and fail. Let's look at some such cases, to be warned early on. Try your understanding of the golden rules and their restrictions, by asking yourself whether the golden rules apply to the following circuits: p.
And will the output's "attempt More Applications: Improved Versions of Earlier Circuits Nearly all the op amp circuits that you meet will do what some earlier open-loop circuit did-but they will do it better. This is true of all the op amp circuits you will see today in the lab.
Let's consider a few of these: current source, summing circuit, follower, and current-to-voltage converter. Vos curve in the "saturation" region a slope that reveals that the FET is not a perfect current source and the more radical departure from currentsource performance in the "linear" region-a region one must stay out of when using a naked FET.
Are you beginning to see how the op amp can do this magic? It takes some time to get used to these wonders. At first it seems too good to be true. Summing Circuit Text sec. Vl'rsion push- puH? We remind you of this because circuit diagrams ordinarily omit the power connections. On the other hand, many op amp circuits make no direct connection between the chip and ground.
Don't let that rattle you; the circuit always includes a ground-in the important sense: common reference called zero volts. Drive the amplifier with a 1kHz sine wave. What is the gain? What is the maximum output swing? How about linearity try a triangle wave? Try sine waves of different frequencies. Note that at some fairly high frequency the amplifier ceases to work well: sine in does not produce sine out.
We will postpone until next time measuring the slew rate that imposes this limit; we are still on our honeymoon with the op amp: it is still ideal: "Yes, sweetheart, your slewing is flawless". Now drive the circuit with a sine wave at 1kHz again. Measure the input impedance of this amplifier circuit by adding lk in series with the input. Measure the output impedance or try to measure it, anyway. Note that no blocking capacitor is needed why? You should expect to fail, here: you probably can do no more than confirm that Zout is very low.
The following curves say this graphically. Vouf fllax -volts 1 5 -3o -2o -1o Source Ho -5 Some gates can turn output off-that means connect out to neither high nor low this is not the same as zero out: King Lear might say, "Nothing will come from nothing Useful if output must go to voltage different from Vee or V Also useful to allow the simplest sort of "OR 'ing" of driving devices.
This is asked in Text exercise 8. Combinational Logic: Minimizing Often you need no such technique: Most of the time, the combinational logic you need to do is so simple that you need nothing more than a little skill in drawing to work out the best implementation.
For such simple gating, the main challenge lies in getting used to the widespread use of active-low signals. Do it the easy way: The easy process for drawing clear, correct circuits that include active-low signals: 1. Draw the shapes that fit the description: AND shape for the word AND, regardless of active levels; Add inversion bubbles to gate inputs and outputs wherever needed to match active levels; Figure out what gate types you need notice that this step comes last.
In general, bubbles meet bubbles in a circuit diagram properly drawn: a gate output with a bubble feeds a gate input with a bubble, and your eye sees the cancellation that this doublenegative implies: bubbles pop bubbles.
Some methods for minimizing If you do neec! Here is a function. How would you implement it? You might proceed in any of several ways: 1. You might simply stare at the table for a while, and discover the pattern. Some people like to work that way.
N 2. Wouldn't it be easy to miss that last step in the simplification process, for example? You might enter the function on a Karnaugh map, and see what simplest form the map delivered: Text. Let's look briefly at the way these maps work. Karnaugh maps: rules Kamaugh maps set out in a two-dimensional form exactly the information carried in a truth table: just a description of the way a circuit should behave. The K-map adds nothing. Here are the rules for the game of K-mapping: group J's in blocks of 1, 2, 4, 8, etc.
What's at stake? Karnaugh-mapping may look like a strange, abstract game unless we consider why we're trying to draw big blobs on the map. Here is another example, showing a map poorly covered with timid little covers , then properly covered with nice big covers. The reward is simpler gating, as you know; but let's look at this particular case. The left-hand map below is covered poorly; the right-hand map is done right. Ulvu cat. K-maps seldom look so good. In fact, now we will admit that you seldom need these maps.
Most problems are too easy or too hard forK-maps. So, don't spend your time getting really good at using K maps. Flops are easy to understand. A harder question arises, however: why are clocked circuits useful? We will work our way from primitive circuits toward a good clocked flip-flop, and we will try to see why such a device is preferable to the simpler flop.
A primitive flip-flop: the "latch" Text sec. It is at the heart of all fancier flip-flops. It looks simple; it also may look fishy, since you can see at a glance that it includes feedback.
That's what makes it interesting: that's what makes it care about its past. Text p. In which state should it rest? How flip it, flop it? This device works, but is hard to design with. It is useful to debounce a switch; but nearly useless for other purposes, in this simplest, barebones form. How does it debounce a switch? To appreciate the difficulty, imagine a circuit made of such primitive latches, and including some feedback.
Imagine trying to predict the circuit's behavior, for all possible input combinations and histories. They wanted to be able to get away with letting several signals change in uncertain sequence, for part of the time. This circuit is just the NAND latch plus an input stage that can make the latch indifferent to signals at S and R: an analog to a camera's shutter. Consider what sort of clock signal you would want, to avoid problems with feedback. Edge-triggered flip flops These flops care about the level of their inputs only during a short time just before and in some rare cases after the clock edge.
An older design, called by the nasty name, master-slave, behaved nastily and was rendered obsolete by the edge-trigger circuit. The master-slave survives only in textbooks, where it has the single virtue that it is easy to understand. The behavior called edge-triggering may sound simple, but it usually takes people a longish time to take it seriously. Apparently the idea violates intuition: the flop acts on what happened before it was clocked, not after. No, this behavior does not violate causality.
How is this behavior possible? Hint: you have seen something a lot like it on your scopes, Class Sequential Circuits: Flip-Flops N which can show you the waveform as it was a short time before the trigger event. How is that magic done? It does not transform it; just saves it. But that simple function is enormously useful. Some flops respond to a falling edge, instead.
As with gates, the default assumption is that the clock is active high. As usual, we have to qualify the "never" slightly: there are some one-shots that trigger on both edges: e. The "never" does seem to hold for flip-flops, though. The transparent latch is such a device. We met this circuit a few pages back. Examples of level-sensitive inputs: 1 A "transparent latch": The character displays we use in this lab work this way called "HP Displays" in lab notes : Figure N Here is a black box diagram of the circuit you are to design: Figure X We'll do it both ways.
Figure X In gate count it's roughly a tie. Use whichever of the two approaches appeals to you. Some people are allergic to K maps; a few like them. Specific advice: In 8. Don't work too hard at K mapping, though. Figure N Questions of timing raise the only interesting issues. For a look at such questions see the Worked Examples on counter use. Modifying count length: divide-by counter Counting as design strategy: a. That's no longer true. IC counters make your work easy. In these notes we'll look at two sorts of problem: first, the easier of the two: making a counter divide by some funny number; second, the more interesting of the two problems: using the counter to make an instrument that measures something.
Not quite so easy; but almost. Synchronous versus Asynchronous Load or Clear It's not hard to state the difference: a synchronous input "waits for the clock," before it is recognized; asynchronous or jam inputs take effect at once after a propagation delay, of course ; they do not wait for the clock. Either one overrrides the normal counting action of the counter. But it is hard to see why the difference matters without looking at examples.
Here are some. Decide whether you want to use Clear or Load, and whether you want these functions to be synchronous or asynchronous. Xl Ch. The short answer is simply that the design obliges the counter to go into an unwanted or false state. There is a glitch: a brief invalid output. You don't need a timing diagram to tell you there is such a glitch; but such a diagram will show how long the false state lasts: CLOCI".
That error would be serious; not just a transient. It is also extremely easy to use. To cut short the natural binary count, restricting the machine to 13 states requires a little logic to detect the 12 state-not the 13, as before. On detecting 12, the logic tells the counter before the clock to clear on the next clock. It's too bad, though, that it requires a NAND. The Text spells out this solution in section 8. The use of Load rather than Clear to define the number of states saves gating, but has some funny side effects.
Or it requires use of a down counter load the initial value; count to zero, use the Borrow signal to load once more: "Borrow," by the way, is just a down-counter's "Carry" signal. This is the technique we use in Lab 15 to make a counter of variable modulus; there, where only frequency concerns us, the technique works fine. So, things are tough all over, and it doesn't matter much which scheme you choose. See Text Table 8. Synchronous load and clear functions are nice: they support the ideal of fullysynchronous design.
Such clears are available on a very few recent registers, as well as on most respectable counters some new counters offer both sorts of clear and load, on four pins: e.
Synchronous functions have not simply replaced asynchronous, because sometimes the synchronous type is a decided nuisance.
See the ornate gating required in order to let one use a pushbutton to load the ' address counters in Lab A jam load would have been just right, there. But most of the time, synchronous functions remain preferable.
Here we will look at a couple of examples of circuits that fail in an attempt to use this arrangement, and then we will go through a longer design exercise where we try to do the job right. X Ch. The relation between digital count and loudness shows a nasty inverse relation. This is a question from an old exam. Problem: counter Application: sonar ranger The Polaroid sonar sensor 1 generates a high pulse between the time when the sensor transmits a burst of high frequency "ultrasound" and the time when the echo or reflection of this waveform hits the sensor.
Only a couple of bursts are sent per second. Design hardware that will generate a count that measures the pulse duration, and thus distance. Let your hardware cycle continually, taking a new reading as often as it conveniently can. Assume that the duration of the pulse can vary between J. You are given a 1 MHz logic-level oscillator.
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