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Reviews 1. Sort: Select. Updating Results. J Jose S. Verified Buyer. What is a Verified Buyer. A Verified Buyer is a user who has purchased the reviewed product through our store. Was this review helpful? Linear Technology Corp. If you wish to place a tax exempt order please contact us. The instrument more than justified the manual's efforts. It was gorgeous.
The integration of mechanicals, layout, and electronics was like nothing I had ever seen. Hours after the thing was fixed I continued to probe and puzzle through its subtleties. A common mode bootstrap scheme was particularly interesting; it had direct applicability to my lab work. Similarly, I resolved to wholesale steal the techniques used for reducing input current and noise.
Life doesn't get any better than this. Unfortunately, Tektronix, Hewlett- Packard, Fluke, and the rest of that ilk had done their work well; the stuff didn't break. I offered free repair services to other labs who would bring me instruments to fix. Not too naany takers. People had repak budgets. Finally, in desperation, Ipaid people in standard MIT currency— Coke and pixza to cteiajerately disable my test equipment so I could fix it. Now, their only possible risk was indigestion. This offer worked well. A few of my students became similarly hooked and we engaged in all forms of contesting.
After a while the "breakers" developed an antiada of incredibly arcMe diseases to visit on the instruments. The "fixers" coun- tered with ever more sophisticated analysis capabilities. Fixing without a schematic was highly regarded, and a consummately macho test of analytical skill and circuit sense. Still other versions rewarded pure speed of repair, irrespective of method. It was also highly efficient, serious education. The inside of a broken, but well-designed piece of test equipment is an extraordinarily effective classroom.
The age or purpose of the instrument is a minor concern. Its instructive value derives from several perspectives. It is always worthwhile to look at how the designer s dealt with prob- lems, utilizing available technology, and within the constraints of cost, size, power, and other realities. Whether the instrument is three months or thirty years old has no bearing on the quality of the thinking that went into it. Good design is independent of technology and basically timeless. The clever, elegant, and often interdisciplinary approaches found in many instruments are eye-opening, and frequently directly applicable to your own design work.
More importantly, they force self-examination, hope- fully preventing rote approaches to problem solving, with their attendant mediocre results. The specific circuit tricks you see are certainly adapt- able and useful, but not nearly as valuable as studying the thought process that produced them. The fact that the instrument is broken provides a unique opportunity.
The one true reason why that instrument doesn't work as it was intended to is really there. You are forced to measure your performance against an absolute, non-negotiable standard; the thing either works or it doesn't when you're finished. A more recent development is "phone fixing " This team exercise, derived by Len Sherman the most adept fixer i know and the author, places a telephone-equipped person at the bench with the brokeatt instrument. Hie paitner, someWtoe else, has the schematic aiid a tetephone.
A surprise is that the llme'-to-fix seems to be kss dm if both parties are physicaliy together. This may be due to dilation of ego factors. Both partners simply must speak and listen with exquisite care to get the thing fixed. Tlie Importance of Fixing The reason all this is so valuable is that it brutally tests your thinking process. Fast judgments, glitzy explanations, and specious, hand-waving arguments cannot be costumed as "creative" activity or true understand- ing of the problem.
After each ego-inspired lunge or jumped conclusion, you confront the uncompromising reality that the damn thing still doesn't work. The utter closedness of the intellectual system prevents you from fooling yourself. When it's finally over, and the box works, and you know why, then the real work begins. You get to try and fix you. The bad conclusions, poor technique, failed explanations, and crummy arguments all demand review. It's an embarrassing process, but quite vahmWe, Yoti learn to dance with problems, instead of trying to mug them. It's scary to wonder how much of this sort of sloppy thinking slips into your own design work.
In that arena, the system is not closed. There is no arbitrarily right answer, only choices. Things can work, but not as well as they might if your thinking had been better. In the worst case, things work, but for different reasons than you think. That's a disaster, and more conunon than might be supposed. For me, the most dangerous point in a design comes when it "works. The luxury the broken instrument's closed intellectual system provides is no longer avaifeble. In design work, results are open to interpretation and explanation and that's a very dangerous time.
When a design "works" is a very delicate stage: you are psychologically ready for the kill and less inclined to continue testing your results and thinking. That's a precarious place to be, and you have to be so careful not to get into trouble. The very humanness that drives you to solve the problem can betray you near the finish line. What all this means is that fixing things is excellent exercise for doing design work.
A sort of bicycle with training wheels that prevent you from getting into too much trouble. In design work you have to mix a willing- ness to try anything with what you hope is critical thinking. This seem- ingly immiscible combination can lead you to a lot of nowheres. The broken instmment's narrow, insistent test of your thinking isn't there, and you can get in a lot deeper before you realize you blew it. The embarrass- ing lessons you're forced to learn when fixing instruments hopefully prevent this. This is the major reason I've been addicted to fixing since I'm fairly sure it was also Jerrold's reason for bouncing my instru- ment repair allocation.
There are, of course, less lofty adjunct benefits to fixing. You can often buy broken equipment at absurdly low cost. I once paid ten bucks for a dead Tektronix A 1 50MHz portable oscilloscope. It had clearly been systematically sabotaged by some weekend-bound calibration technician and tagged "Beyond Repair.
TTiis kind of devotion highlights another, secondary beneik of fixing. There is a certain satisfaction, a kind of service to a moral inaperative, 6 that comes from restoring a high-quality instrument. This is unquestion- ably a gooey, hand-over-the-heart judgment, and I confess a long-term love affair with instrumentation. It just seems sacrilege to let a good piece of equipment die. Finally, fixing is simply a lot of fun, I may be the only person at an electronics flea market who will pay more for the busted stuff! This page intentionally left blank Barry Harvey 2. How to Grow Strong, Healthy Engineers Graduating engineering students have a rough time of it lately.
Used to be, most grads were employable and could be hired for many jobs. Ten years ago and earlier, there were a lot of jobs. Now, there aren't so many and employers demand relevant course work for the myriad of esoteric pursuits in electrical engineering. Of those grads that do get hired, the majority fail in their first professional placement. We should wonder, is this an unhealthy industry for young engineers?
The Art and Science of Analog Circuit Design. EDN Series for Design Engineers
Well, I guess so. Although I am productive and comfortable now, I was not successful in my first three jobs, encompassing nine years of profes- sional waste. Although I designed several analog ICs that worked in this period, none made it to market. Let me define what I call professional success: The successful engineer delivers to his or her employer at least 2M times the yearly salary in directly attributable sales or efficiency.
It may take years to assess this. For many positions, it's easy to take this measure. For others, such as in quality assurance, one assays the damage done to the company for not executing one's duties. This is more nebulous and requires a wider busi- ness acumen to make the measure. At this point, let me pose what I think is the central function of the engineer: Engineers create, support, and sell machines. That's our purpose. A microprocessor is a machine; so is a hammer or a glove. It doesn't stop with the designer: the manufacturing workers and engi- neers really make the machines, long-term.
There's lots of engineering support, and all for making the machines and encouraging our beloved customers to buy them. Some people don't understand or savor this defi- nition, but it's been the role of engineers since the beginning of the in- dustrial revolution. I personally like it. I like the structure of business, the creation of products, the manufacture of them, and the publicizing of them. Our products are like our children, maybe more like our pets. They have lives, some healthy and some sickly. Four of my ICs have healthy, popular lives; ten are doing just OK; and six are just not popular in the market.
Others have died. A young engineering student won't ever hear of this in school. Our colleges' faculties are uneasy with the engineers' charter. The students 9 How to Grow Strong, Healthy Engineers don't know that they will be held to standards of productivity. They are taught that engiiieering is like science, sort of. But science need not pro- vide econoniic virtue; engineering pursuits must.
So what is the state of engineering for the new grad? Hope- fully, the grad will initially be given procedural tasks that will be suc- cessful and lead to more independent projects. At worst, as in my experience, the young engineer will be assigned to projects better left to seasoned engineers. These projects generally veer off on some strange trajectory, and those involved suffer. Oddly enough, the young engineer receives the same raises per year for each possibility. What, then, is the initial value of a young engineer? The ability to support ongoing duties in a company? Design ability due to new topics available in academia?
Probably not, for two reasons. First, colleges typi- cally follow rather than lead progress in industry. Second, new grads can' t seem to design their way out of a paper bag, in terms of bringing a design through a company to successful customer acceptance. Not just my opinion, it's history. This is what's wrong with grads, with respect to the electrcmics industry: They are not ready to make money for their new employer.
They don't know they're not scientists; that engineers make and sell things. They don't appreciate the economic foundation we all oper- ate with. They don't know just how under-prepared they are. Hiey are Sopho- mores — from the ancient Greek, suggesting "those who think they know. They have hubriSy the unearned egotistical satisfaction of the young and the matriculated.
They see that many of their superiors are jerks, idiots, incompetents, or lazy. Well, sure. Not in all companies, but too often true enough. Our grads often proclaim this truth loudly and invite unnecessary trouble. They willingly accept tasks they are ill-suited for. They don't know they'll be slaughtered for their failures. Marketing positions come to mind. Not all grads actually like engineering.
They might have taken the career for monetary reward alone. These folks may never be good at the trade. So, should we never hire young engineers? Should we declare them useless and damn them to eternal disgrace? Should we never party with them? Well, probably not. Anyway, young people really do add vitality to our aging industry. It behooves us all, then, to create a professional growth path where the company can get the most out of its investment, and the new grad can also get the most lifelong result from his or her college investment.
I have a practical plan. I didn't invent it; the Renaissance tradespeople did. It's called "apprenticeship. The work was the production of household art. This might be devotional paintings, could be wondrous inlaid marble tables, might be gorgeous hand-woven tapestries to insulate the walls. In most cases, the artistic was combined with the practical. Let me amplify: the art was profitable. There was no cynicism about it; beauty and commerce were both considered good. We have simile attitudes today, but perhaps we've lost some of the artistic content. Too bad: our industrial management has very little imagi- nation, and seldom recognizes the value of beauty in the marketplace.
At Elantec, we've made our reputation on being the analog boutique of high-speed circuits. We couldn't compete on pure price as a younger company, but our willingness to make elegant circuits gave us a lot of customer loyalty. We let the big companies offer cheap but ugly circuits; we try to give customers their ideal integrated solutions.
We truly like our customers and want to please them. We are finally competitive in pricing, but we still offer a lot of value in the cheaper circuits. Do college grads figure into this market approach? Not at all. Just ain't taught. The Renaissance concept of the "shop" will work, however. The shop was a training place, a place where ability was measured rather than assumed, where each employee was assigned tasks aimed for success. Professional growth was managed. An example: the Renaissance portrait shop. The frame was con- structed by the lowliest of apprentices. This frame was carved wood, and the apprentice spent much of his or her time practicing carving on junk wood in anticipation of real product.
The frame apprentice also was taught how to suspend the canvas properly. Much of the area of the can- vas was painted by other apprentices or journeyman painters. They were allowed to paint only cherubs or buildings or clouds. The young painters were encouraged to form such small specialties, for they support deeper abilities later. So many fine old paintings were done by gangs; it's sur- prising.
Raphael, Tintoretto, and even Michelangelo had such shops. Most of the master painters had been apprentices in someone else's shops. We get our phrase "state of the art" from these people. Today's engineers do practice an art form. Our management would probably prefer that we not recognize the art content, for it derails How to Grow Strong, Healthy Engineers traditional business management based on power.
We engineers have to ensure that artistic and practical training be given to our novices. So, how does one train the engineering grad? I can only speak for my own field, analog IC design. I'll give some suggestions that will have equivalents in other areas of engineering. The reader can create a pro- gram for his or her own work. The grad will initially be given applications engineering duty. Applications is the company's technical link with the buying public. TOs group answers phone calls of technical inquiries and helps customers with specific problems with the circuits in the lab, when published or designer information is unavailable.
Phone duty is only half of applica- tions; they develop applications circuits utilizing products and get the write-ups published, typically through trade magazines such as EDN. They produce application notes, which serve as practical and educational reading for customers. My first two years in the industry were in this job. In one instance, I forced a redesign of a circuit I was preparing the data sheet for because it simply did not func- tion adequately for the end application.
Of course, designers always think their circuits are good enough. A truly seasoned applications engineer can be involve in new product selection. Making application notes would be required, guided by senior applications engineers. I believe thM devel- oping good engineering writing skills is important for the designer. After a couple of months, the engineer would start phone duty. It's important that the engineer be optimally professional and helpful to the customer so as to represent the company best.
Most of us have called other companies for help with some product problem, only to reach some useless clone. This stint in applications would last full-time for six months, then be continued another six months half-time, say mornings for us West Coast folks. In ana- log IC circuit design, it's very important to use accurate and extensive model parameters for the circuit simulators. Not having good models has caused extensive redesign exercises in our early days, and most designers in the industry never have adequate models. As circuits get faster and faster, this becomes even more critical.
Larger companies have modeling 12 groups, or require the process development engineers to create models. I have found these groups' data inaccurate in the previous companies where Fve worked. We recently checked for accuracy between some device samples and the models created by a modeling group at a well-known simulator vendor, and the data was pure garbage. We modeled the devices correctly ourselves. This being a general design need, I would have the young engineer create model parameters from process samples, guided by a senior engi- neer with a knack for the subject.
This would also be an opportunity to steep the engineer in the simulation procedures of the department, since the models are verified and adjusted by using them in the circuit simulator to play back the initial measurements. It's a pretty tedious task, involving lots of careful measurements and extrapolations, and would probably take three months, part-time, to re-characterize a process. Modeling does give the engineer truly fundamental knowledge about device limitations in circuits and geometries appropriate to different circuit applications, some really arcane and useful laboratory techniques, and the appreciation for accuracy and detail needed in design.
Because of the tedium of modeling, few companies have accurate ongoing process data. Most of our de- signers at Elantec have done the mask design for some of their circuits, but this is rare in the industry. The usual approach is to give inadequate design packages to professional mask designers and waste much of their time badgering them through the layout. The designer often does an inad- equate check of the finished layout, occasionally insisting on changes in areas that should have been edited earlier.
When the project runs late, the engineer can blame the mask designer. You see it all the time. I would have the young engineer take the job of mask designer for one easy layout in the second three months of half-time. He would lay out another designer's circuit and observe all the inefficiencies heaped upon him, hopefully with an eye to preventing them in the future. The first real design can be started at the beginning of the second year. This should be a design with success guaranteed, such as splicing the existing circuit A with the existing circuit B; no creativity desired but economy required.
Hiis is a trend in modem analog IC design: elaborating functions around proven working circuitry. The engineer will be overseen by a senior engineer, possibly the designer of the existing circuitry to be retrofitted. The senior engineer should be given management power over How to Grow Strong, Healthy Engineers the young engineer, and should be held responsible for the project results. We should not invest project leadership too early in young engineers; it's not fair to them. The engineer will also lay the circuit out, characterize it, and make the data sheet.
Each step should be overseen by an appropriate senior engineer. The engimer now has been led through each of the steps in a design, except for product development. Here the designer we'll call the young engineer a designer only when the first product is delivered to production takes the project details from the marketing department and reforms them to a more producible definition of siUcon.
At the end of the initial product planning, the designer can report to the company what the expected specifications, functionality, and die size are. There are always difficulties and trade-offs that modify mar- keting's initial request. This should be overseen by the design manager. The project will presumably continue through the now-fanwliar sequence.
The designer should be allowed to utilize a mask designer at this point, but should probably characterize the silicon and write the data sheet one last time. This regimen takes a little over two years, but is valuable to the com- pany right from the start. In the long mn, the company gains a seasoned designer in about three years, not the usual seven years minimum.
It's also an opportunity to see where a prospective designer will have difficul- ties without incurring devastating emotional and project damage. The grad can decide for himself or herself if the design path is really correct, and the apprenticeship gives opportunities to jump into other career paths.
I like the concepts of apprentice, journeyman, and master levels of the art. If you hang around in the industry long enough, you'll get the title "senior" or "staff. I have met very few masters at our craft; most of us fall into the journeyman category. I put no union con- notation on the terms; I just like the emphasis on craftsmanship.
There are a few engineers who graduate ready to make a company some money, but very few. Most grads are fresh engineering meat, and need to be developed into real engineers. It's time for companies to train their people and eliminate the undeserved failures. We should guide grads through this kind of apprenticeship to preserve their enthusiasm and energy, ensuring a better profession for us all. Myself, I specialize in purely technical writing. But after Jim gave me the opportunity to offer something for the second book, the first book seemed more right and I couldn't resist this chance for blatant editorialization.
Fm mad, see, mad about the waste of young engineers. Waste is bad. This page intentionally left blank Barry Harvey 3. My employer sponsors the hobby I've had for thirty of my forty-year life. We don't disagree much; I like most of the aspects of my job, even the tedious ones. However, I'm no lackey. I don't really listen to many people, although I try to appear to.
There's no cyni- cism here; all my associates agree with me that we will produce nifty new ICs and make money. That's the job. This entry of Jim's compendium is offered to relate what an earlier generation of engineers experienced in preparation for a career in elec- tronics. Many of my associates were quite functional in electronics when they entered college.
We were apparently different from most of the stu- dents today. We were self-directed and motivated, and liked the subject. I have detected a gradual decrease in proficiency and enthusiasm in college graduates over the last fifteen years; perhaps this writing will explain some of the attitudes of their seniors. I've included some photographs of lovely old tube equipment as background.
My experiences with electronics started with constmction projects in- volving vacuum tubes, then transistors, eventually analog ICs, raw micro- processor boards, and finally the design of high-frequency analog ICs. Through all the years, I've tried to keep the hobby attitude alive. I'm not patient enough to grind through a job for years on end if I don't really enjoy it. I recommend that anyone who finds his or her job boring decide what they do like to do, quit the current job, and do the more enjoyable thing. My first memory of vacuum tubes is a hot Las Vegas, Nevada morning around 1 a.
I was young, about ten years old. As I lay listening to the music I noticed that the tubes of the radio projected more blue light on the ceiling than the expected yellow-red filament glow. It's hard to imagine that simple, beautiful, blue projection upon your wall which comes from the miniature infemo within the tubes.
It comes from argon gas which leaks into the tube and fluoresces in the electric fields within. Occasionally, you can see the music modulate the light of the output tubes. It was built in the mids, so it was made of cheap pine with ash or maple?
Typ- ical of the times, it had sweeping rounded comers between the top and front, and inlaid edging. They never did figure out how to make a true accurate comer with cheap wood processes. At length. Radios were magic then, TV wasn't nearly as entrancing as now, being black-and white in most homes and generally inane the good adult stuff was on too late for me to see. On radio you heard world news, pretty much the only up-to-the-minute news. You heard radio stations that didn't know from anything but variety in music. When I was that young, the people who called into the talk shows were trying to be intelli- gent, Shows what an old fart I am.
The electronic product market of the time was mostly TV and radios. Then you also got a big console, radio, speakers, and Figure A lovely TRF radio from the s and '30s. This was before superheterodyne reception; you had to tune ail three dials to get your station. More or! A lot of fami as well as city dwellers used these. The coils were hand-wound, and every component was available for scrutiny This set will be usable after a nuclear attack. Photo by Caleb Brown. We pay only a little more for similar but better today. Lab equipment was really rotten then compared to today. There was no digital anything.
Want to measure a voltage? I eventually did wreck it, using it on a wrong range. In the vacuum-tube days, things burned out.
Full text of "Electronics: The Art And Science Of Analog Circuit Design (PCB)"
The tubes might only last a year, or they might last 20 years. Early 2- watt resistors had wax in them, and always burned out. The later carbon resistors could still bum out. When 1 say bum out, I mean exactly that: they went up in smoke or even flame. That's where the term came from. Where we have cute switching power supplies today, then the tubes ran from what we call "linear" supplies that included power transformers which in quality gear weighed a dozen pounds or more. The rectifiers might be massive tubes, or they could be selenium rectifiers that also burned up, and they were poisonous when they did.
The bypass capacitors were a joke. They would eventually fail and spew out a caustic goop on the rest of the innocent electronics. Let's face it, this stuff was dangerous. I almost forgot to mention the heat. A typical vacuum tube ran hot; the glass would bum you if you touched it. The wood cabinets needed to be regularly oiled or waxed because the heat inside discolored and cooked them. A power tube ran really hot, hot enough to make the plate glow cherry-red in normal operation. You could get an infrared sunburn from a few inches' proximity to a serious power tube.
From a couple of feet away your face would feel the heat from an operating transmitter. But it wasn't bumout or heat that was the most dangerous thing to an electronics enthusiast; it was the voltage.
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The very wimpiest tube ran from 45V plate potential, but the usual voltage was more like V for a low-power circuit. I made a beautiful supply for my ham transmitter that provided V for the output amplifier. Naturally, it knocked me across the room one day when I touched the wrong thing; a kind of coming-of- age ritual. This event relieved me of all fear of electricity, and it gave me m inclination to think before acting. Nowadays, I sneer at bare electrodes connected to semiconductors. I routinely touch nodes to monitor the ef- fect of body capacitance and damping on circuit behavior.
I have often amazed gullible peasants by curing oscillations or fixing bypasses with only my touch. Of course, the off-line power supplies command my re- spect. For them, I submit and use an isolation transformer. At this point, I think we can explain the lack of females attracted to electronics at Ae time. In the 50s md 60s, society protected women but offered men up to danger.
The same is tme for the earlier industrial revo- lution: women were huddled into protective work environments and men were fodder for the dangerous jobs. I think this attitude was prevalent with respect to vacuum tube electronics. Women girls, in particular We Used to Get Burned a Lot, and We Uked It were not encouraged to enjoy the shock hazards, the bums, the excessive weights of the equipment, or the dirtiness of the surfaces. Boys, of course, found all this attractive. I suppose this is the historical basis of the male domination of the field. The duress of dealing with this kind of electronics really appealed to young men's macho, just like work- ing on cars appealed to the gearhead set.
The difference between the groups was that electronics required a lot more education and intellect than cars, and so appealed to more bookish types. The girls never caught on to how cool electronics was, probably because a radio can't get you out of the house. The electronics hobbyists creators of today's nerd stereo- type simply found another way to get away from the parents. It worked; the old folks really did keep out of the garage, the rightful dominion of hobby electronics. A social difference between then and now is how much more prevalent hobbies were.
As I mentioned, TV did not occupy as much of people's time. Kids got as bored as now, so they turned to hobbies. When boys got together, they needed something to do, and they could share cars or elec- tronics, This led to a much more capable young workforce, and getting a job after high school seemed easier than now. Furthermore, you probably had strong interests that could guide you through college.
Changing ma- jors or not having a major was unusual. Now, kids are generally far less self'directed. They haven't had to resolve boredom; there's too much en- Figure An original breacfcoard. You can really see your solder joints in this construction style. Barry Harvey tertainment easily available to them today. Further, drugs destroy hobbies. As a result, the college students I've interviewed over the years have grad- ually lost pre-coUege experience with their field.
Twenty years ago college grads had typically been working with electronics for two to seven years before college, and the new grad could perform well in industry. Regret- tably, it now takes up to three years of professional experience to build a junior engineer, titles notwithstanding. Perhaps worse is the attitude change over the years. Iiicreasingly, the grads are in electronics for the bucks, and seldom play in the art for their own amuse- ment. Present company excepted; I know the readers of this book are not in that category. To be fair, present electronics focuses on computers and massive systems that are hard to comprehend or create in youth.
Con- struction of projects or repairing home electronics is mostly out of the realm of kids not encouraged by a technical adult. I think this places an obligation on families and schools to support elec- tronics projects for kids, if we are to generate really capable and wise engineers in the future. By the time a present grad has had enough years of experience to become an expert in some area, the technology is liable to change.
Breadth of technical experience is the only professional answer Rgure A really beautiful radio from the 1 s. A so-called Tombstone radio; the fins are wood decoration. This is elec- tronics as furniture; the radio is good but the cabinet is exquisite. The dial is artistic and several frequency bands await the curious. Not fully visible is the same radio flanked by different cabinets made by competitive groups within Zenith, From the John Eckland Collection, Palo Alto, California.
Employers do not encourage nor support the engineer's development outside his narrow field, so breadth seems something best developed by hobbies before college, and a more varied engineerinqg train- ing during college. But we digress. Somewhere around I saw the first transistor ra- dios. They were kind of a novelty; they didn't work too well and were notoriously unreliable. They replaced portable tube radios, which were just smaller than a child's lunch box. They weighed about seven pounds, and used a 45V or 67V battery and a couple of "D" cells for the fila- ments. These tubes were also used in satellites and were quite good.
Even so, the transistor radios were instant winners. They were cheaper than any tube radio, were truly portstole, and could be hidden in classrooms. The miniature earphone really made it big. The transistor radio easily doubled the audience for musicians and advertisers. Perhaps it was the portable transistor radio that accounted for the explosive growth of rock music. While it's true that rock-and-roll was popular as hell in the late 50s and early 60s, the sales of records and the number of radio stations just didn't compare with the activity at the end of the 60s. As I said, the transistor radios were unreliable.
I made spending money repairing radios when I was in grade school. Replace- ment parts were grudgingly sold by TV repair shops; they'd rather do the servicing, thank you. Hie garbage line of 2SK-prefix transistors was of- fered. These Japanese part numbers had nothing to do with the American types and surprisingly few cross-references were available. I had no equipment, but most of the failures were due to gross construction or device quality problems.
Only a few years after the transistor radios emerged they became too cheap to repair. They made for a poor hobby anyway, so I turned to ham radio. This was the world-wide society of folks who lUce to taBc to each other. The farther away the better; it's more fun to talk to a fellow in Panama than one in Indiana.
People were more sociable then, anyway. The world community seemed comfortably far off and "foreign" had an attraction. I didn't have enough money to buy real commercial ham gear. Luckily for me, many hams had the same inclinations as I and a dynamic home- construction craze was ongoing. Hams would build any part of a radio station: receivers, transmitters, or antennas.
They were quite a game group of mostly guys , actually; grounded in physics and algebra, they used little calibrated equipment but actually furthered the state of radio art. Congress gave them wide expanses of spectrum to support this re- naissance of American engineering. The base metal is chrome-plated for longevity. All coils are shielded in plated housings, and string tuning indicator mechanisms are replaced with steel wire, These components are as uncorrupted as they were when they were made in The designers gave extra attention to the quality of everything the customer would see and feel the knobs play very well.
Hams performed feats of moon bounce communi- cations and even made a series of Oscar repeater satellites. Some fun. Soon after transistor radios were common, industrial transistors became cheap and available in volume. The hobby books were out with good cir- cuit ideas in them, so I finally started making transistor projects about Tbbes were still superior for the hobbyist because of their availability.
You could salvage parts from radios and TVs found at the dump, or discarded sets awaiting the trashman. Because the circuits were relatively simple, we would dismantle old sets right down to separated components and chassis, which would be reassembled into the next hobby project. I began to tap the surplus parts suppliers, and the added supply of tube and related parts delayed my interest in solid-state circuits. The first commercial transistors were germanium PNP, and they sucked.
Being decorative, tlie cabinet and dial are of good quality, hi tlie upper-right corner is a magie-eye tube, an oscilioscope-lilte gizmo that gives an analog indication of tuning accuracy Rom the John Eckland Collection, Palo Alto, California. Their Vbe went to zero at IWC; that is, the whole transistor be- came intrinsic and was a short-circuit.
You didn't bother making instrumentation circuits with those devices; there just weren't any matched pairs to be found. The Vbe's also suffered from terrible long-term drift, I think because germa- nium could never be alloyed adequately for a solid contact. What really made my decision to use transistors was the advent of the silicon NPN device, Silicon could tolerate temperature, and was insensi- tive to excessive soldering- It never went intrinsic, and beta control al- lowed for matched pairs.
The high-quality differential input stage made the industry of hybrid op amps possible, and some of them could handle the same signal voltages as the tube op amps. Silicon transistors even gave decent frequency responses, although the faster devices were still electrically delicate. Silicon made TVs and radios work better too.
Circuit design changed overnight. The threshold voltage of tubes analogous to the threshold of JFETs would vary over a 3: 1 range. Because of the poor bias point accuracies, most circuits were AC cou- pled. This precluded them from many industrial applications. Although Bairy Harvey Figure The uncertainty of transistor Vbe was really negligible, relative to supply voltages, and biasing transistors was a snap, although not widely understood then.
But between and , the choice of transistor or tube was often made by the prejudice of the designer. Some applications demanded one device or the other, but in the case of audio amplifiers, there was free choice.
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Construction of electronics changed radically in this time. Tubes were mounted in sockets whose lugs served as the supports for components, and a solid steel chassis supported the circuits. Steel was necessary, since the tubes couldn't tolerate mechanical vibration and the massive power supplies needed support. The most elegant construction was found in Tektronics oscilloscopes.
They used molded ceramic terminal strips to support components, and only about eight components could be soldered into a pair of terminal strips. Cheaper products used Bakelite strips. The assemblies were also very three dimen- sional; the tubes sprouted vertically above the chassis by three to five We Used to Get Burned a Lot, and We Liked It inches and the other components sprawled in a two-inch mat below the chassis. Transistors made construction more two dimensional. Hie transistors weren't tall, generally the size of our TO package of today, and circuit boards were practical since they didn't have to support heavy or hot com- ponents.
A layer of transistor circuitry thinned to one inch or less. There was a volume reduction of about over equivalent tube circuits. For industrial electronics, how- ever, transistors afforded only a overall product cost reduction. Transistor equip- ment was considered cheap, relative to tube gear, and only received cheesy plastic cases. The paint and decals on the plastic rubbed or flaked off, and impact could shatter it altogether. Tube equipment, on the other hand, bad enjoyed quality wood casings for decades. Since the tube chas- sis were so large and heavy, furniture-quality cabinets were needed sim- ply to transport the electronics.
The radios and TVs were so obtrusive in tube forni that manufacturers really made the cabinets fine furniture to comply with home decor. Quality in the tube years came to mean both mass and the use of pre- cious materials. Greater mass meant you could transport or physically abuse the equipment with no damage.
It also meant that the components would suffer less from thermal changes and microphonics felcctrical sen- sitivity to mechanical vibrations. A really sturdy chassis would not need alignment of the tuned circuits as often as a flimsy frame. Pracious mate- rials included quality platings — such as chrome or vanadium — of the chassis, to avoid corrosion and extend useful Ufe.
Heavier transformers allowed more power for better bass response and greater volume, A heav- ier power transformer would bum out less frequently, as would oversize power tubes. Components came in quality levels from cheap organic- based resistors and capacitors that cockroaches could eat to more expen- sive and long-lived sealed components. The general attitude about electronics construction was akin to furniture: the more mass and the more precious the material, the better Since the transistor circuits had no thermal nor microphonic problems, the poorest of cases were given to them.
They weighed next to nothing, and a hard fall wouldn't cause too much damage. Since the products had no mass nor special materials in their construction, people thought of transistor products as low-quality. The manufacturers made sott this was true by using the poorest materials available. The circuit boards did in- deed tamish and warp, and the copper could crack and cause opens. The wires soldered to the boards seemed always stressed from assembly and often broke. Even the solder had corrosive rosin. Because the transistor circuits were small, the traditional soldering guns and irons were far too hot and large to use; we now had to buy new small irons.
We even had to get more delicate probes for oscilioseopes and voltmeters. These problems were moot; you couldn't effectively repair transistor stuff then anyway. Even if you could troubleshoot a bad 26 Bdrry Harvey Figurt Electronics for the masses: the Knight-Kit audio amplifier. You could not make a profit repairing transistor products. It got harder to make hobby circuits too. In the mid'60s, printed circuit boards were so bad you might as well try to make your own.
So I bought a bottle of ferric chloride and tried it myself. For masking, I tried direct painting house exterior paint wasn't bad and resist ink pens. These are the pre- etched general-purpose breadboards in printed circuit form. They had DIP package regions and general O. Analog hob- byists would obediently solder interconnect wires between pads, but the digital hobbyists had too many connections to make and adopted wire-wrap construction. Suddenly construction projects lost their artistic appeal. You could hardly see the connections of transistor circuits, and this only got worse as ICs displaced groups of transistors, I knew a couple of old codgers who gave up hobby electronics due to failing eyesight.
Funny thing was, semicon- ductor projects still cost as much as tube equivalents but were uglier, more difficult to build, and harder to debug and tune. At work you built circuits on higher-quality breadboards. But within only a few years, critical ICs were available in surface-mount packages, or more expensive and clumsy socketed alternatives.
ITie pin count of the packages just skyrocketed. The sockets are expensive and fragile. A transition began which is almost complete today: breadboards are simply not attempted to develop each subsystem of a board; the first tentative schematic will be laid out on a full-fledged circuit board. Any corrections are simply implemented as board revisions. These boards contain mostly surface-mount components. They are generally multilayer and the individual traces can't be seen, so finding interconnects is impossible.
The only connections that can be probed or modified are the IC's leads themselves. You generally can't read the markings on resistors or capacitors, because they are so small Develop- ment work is accomplished with stereo microscopes. So hobby electronics has taken a major beating in the last twenty years. It's become intellectually difficult to build a really significant proj- ect, to say nothing of increased expense and construction difficulty. This portends a generation of relatively green engineers who have only coltege experience with electronics.
God help us. I suppose there still are some handy people, as demonstrated by the continuing component sales of Radio Shack. Too bad that they have diminished the component content of their stores over the years, and traditional hobby suppliers like Lafay- ette and Heathkit have altogether disappeared. There is no substitute for pre-college electronics experience. Gone too is the magic people used to see in electronics.
As a kid, I saw that other kids and their parents were amazed that radios and TVs worked at all. Our folks used to think of installing a TV antenna as an electronics project. Parents gave their kids science toys. These were great; we had chemistry sets, metal construction kits, build-your-own-radio-from- household-junk sets, model rockets, crystal-growing kits, all sorts of great science projects. The television stations even kept Mr.
Wizard alive, the weekly science experiment program. It seems now that people assume they can't understand science or technology, and accept this ignorance. Kind of like religious belief. We even predict future advancements when we have no idea how to accomplish them. We don't give our young children these science toys, even though the kids would find them wondrous. Parents are imposing jaded attitudes on kids. This would be all right, except that electronics has grown in scope beyond the ability of college to teach it well. Students graduating today have insufficient breadth of knowledge of the field, and not enough depth to really take on a professional project.
I don't blame them; it's probably 28 impossible to be the master of anything with a college diploma but no real experience. I don't know all of the answers, just the problem. As long as our soci- ety considers engineering unglamorous and nerdy, kids won't be attracted to it. Industry will wonder why young engineers are not highly produc- tive. Companies never really train people; they just give them opportuni- ties.
We'll see a general malaise in design productivity, just as we now see a problem with software production. I could be getting carried away with all this, but we should promote science and technology as suitable hobbies for our kids. This page intentionally left blank Keitaro Sekine 4. Analog Design Productivity and the Challenge of Creating Future Generations of Analog Engineers Introduction Recently, digital techniques are very commonly used in the fields of elec- tronics. This reflects to a analog vs.