Electronic Design

Bob's Mailbox

Dear Bob:
About hollerin'... I enjoyed your article about hollerin' in the June 10 issue. I agreed totally with your opinions, right up until you said "Ideally, we shouldn't have to holler at anybody."

Well, first, it's obvious that God made our lungs and larynx so that we can holler, ergo it must be something we're supposed to do. No, I happen to believe that hollerin' is a useful tool, not just something to do when you bash your thumb with a hammer. A few specific cases illustrate this point.

Back in high school I earned my keep one summer teaching in a reading skill improvement program for dyslexic students. We took these pupils, guys Montessori wouldn't touch, and in about eight weeks raised their reading level an AVERAGE of 2.5 grade levels. The technique, developed by Dr. Charles Shedd, involved simultaneous stimulus of most of the human senses during a learning session. We had 50 instructors with 50 students in a school lunchroom all hollerin' "See Spot run!" at the top of our lungs for six hours every day. The aforementioned results speak for themselves. I also found, after a few days, that all that hollerin' didn't bother my concentration one bit. Perhaps I'm a little bit dyslexic, too.

Next case in point is far more recent. I enjoy coaching youth football every fall. As you might suspect, football involves a lot of hollerin', and I tell my parents so right up front. Last year I had a mother come to my wife after one or two practices saying that her son was upset that I was hollerin' at him. "What did he say to your son?", she asked. The mother answered with a big grin, "He yelled, `Good job!'" That kid has developed into one of my finest linemen, and he hollers encouragement to his teammates. Sometimes when I holler at him, he hollers back. Now we're getting somewhere.

I used to be the kind that held everything in. This resulted in busted telephone handsets and chairs throw through walls at work. More recently, I have started practicing some hollerin' concepts outside the confines of the football field. My co-workers and management seem more satisfied with this approach. My wife is not so sure. Anyway, I think that since you seem to be more advanced than others of us in this area, you should author a guide book, perhaps entitled The Art of Hollerin'. Topics for the novice workplace hollerer could include when to Holler at the phone, when to Holler INTO the phone, Whether to Cuss or just Holler, and how to be Hollered At. Having decided that hollerin' makes me a more well-rounded individual, it is these finer points that need attention!
Principal Member I
Ford Microelectronics

WELL, I wonder who figured out that HOLLERING is good for curing dyslexia. It is WELL KNOWN that hollering works well on football players. Maybe it was found to work on a dyslexic left guard?? "See Spot run to daylight..." I'll let YOU write the HOLLERING guidebook. — RAP

Haven't felt the urge to write for some time but your comments about hard drives, floppies, etc., in June 24 issue tweaked some strings with me.

The first laptop I owned was a Tandy Model 100 with 32 k of battery-supported static RAM, no floppies, and a little audio-cassette machine for mass storage. Cost me $300 on sale. Carried the critter everywhere and used it a lot! Got a burr under my saddle one day and bought a two-floppy, DOS machine. Now I was REALLY moving up... except the battery life was only about three hours and it took 14 hours to recharge. Further, the battery was internal. But the screen WAS larger and backlighted so... what's a little hassle about battery life?

About a year later I saw a laptop with 20-Meg hard drive and removable batteries on sale. Wow! Just what I needed! Unfortunately, battery life wasn't much better. It took six batteries for a round-trip to the East coast. Further, the thing wouldn't fit in my briefcase, and it cost 2 kilobucks... worried about the durn thing a lot in airports.

Another year later, I stumbled onto a special interest group for the Model 100 Tandy machines on Compuserve and was reminded of what I once had: More RAM than I could fill on one trip, eight hours of battery life on AA cells available from any airport gift shop, fits inside my briefcase, and here's the best part — bought two of them off of Compuserve for $100 apiece. Carry one every trip and get lots of writing done. A serial cable lets me dump contents to the desktop machine when I get home for finishing work. Keyboard is full-sized, key action is good, and the screen is 8 by 40 with really fat characters so I can work without my "cheaters." If I drop one on its head, I'm only out $100 and the time it took to fill less than 32 k of RAM. I'm computer-poor with byte-thrashing desktops but when I travel, my favorite NO-FLOPPY machine goes along. Took it to Portland last week and wrote two articles. There's a not-so-old saying I've been sharing for several years now, "Try as one might, it's difficult to make much of an improvement upon the hammer."
Consulting Engineer
Wichita, Kansas

Well, if modern technology were applied to a Tandy 100, it would sure have some nice advantages. The whole idea that a laptop has to be ready to spring into action at 100 MHz while you sit there typing away at 0.000003 MHz sure seems bizarre to me. Not to mention those power-hungry color displays... Maybe you can tell me where I can buy one of those old Tandy 100s...? I went by a Radio Shack yesterday, but the Model 100 is discontinued. Sigh. — RAP

Dear Bob:
In your May 1 column in Electronic Design, you said in part: "Modern etched circuit boards...really do improve uniformity of performance, and reliability, too. I mean, old hand-wired Tek scopes were not terrible, but nobody would want to do without the advantage of modern wave-soldered circuit boards." You denigrated Tek, (and indirectly Zenith, since the reader referred to them.) Those two companies were to me the paragons of beautiful design and construction when I was first learning.

We have had several hand-wired Tek scopes, and even after 30 years (yes, we have 30-year-old Teks we still use occasionally), I never have seen any problems with bad solder joints. (The same goes for the old Zenith TV sets.)

In contrast, I've got a modern 26-in. stereo TV in our bedroom that I got for free — all I had to do was fix it. The problem? A bad solder joint on the circuit board at a main power-supply choke. Same thing for a modern color TV at our vacation shack. A sudden craziness in the green gun action fixed by resoldering. I see a lot of problems with wave-soldered boards. Often, with smaller boards, a brute-force technique of "resolder everything" will do wonders for an intermittent.

In the 50s, Mad-Man Muntz could sell TVs for half of what Zenith was charging, because he designed them cheaply and built them cheaply. TV repair shops loved Muntz, he provided a lot of work for them. Wave-soldering has done wonders for the COST of electronic equipment, but dependability is mostly a factor of quality of design and construction. Today the names are different, but there are still the Zeniths and the Muntzs.

You missed that one Bob!
FRANK R. BORGER, Physicist
Department of Radiation Therapy
Chicago, Ill.

There have been (fairly) reliable circuits in the past, and there are reliable ones now. But I'd hate to think of a Pentium PC with hand-wiring! It might not be impossible, but it sure wouldn't be cost-effective. And I'd hate to have to troubleshoot the ones hat didn't work! NOW, the reliability and integrity of the wiring is just PART of the system's reliability. You need to buy reliable parts, and the system must be engineered to avoid stupid misapplications. Building good, reliable circuits is not trivial — never was. — RAP

Dear Mr. Pease
Regarding "What's All This Caffeine Stuff, Anyhow?" in the Feb. 19 issue, I recall a study on the effects of caffeine as well. It may well be the same as the engineer pointed out. What I recall is not quite the same, though. Yes, the workers on caffeine "felt" that they were being more productive and "felt" more positive, etc. However, metrics of their actual performance showed that they were fooling themselves. The noncaffeinated participants actually performed MORE work. They just didn't "feel" like they did.

I cannot recall whether the non-caffeinated were being forced through withdrawals during the experiment, but their report of their "feelings" seemed to indicate so. I would like to see a good comparison of habitual caffeine dosers against the caffeine-free, if someone is going to make generalizations of this nature. Having freed myself from the caffeine tyranny, I can observe the effects that an occasional caffeine burst does for me. (No coffee, please, just that green Mountain morning mist tea, or JOLT! for those late night spec write-ups.) It seems to act very much like refined sugar does. Elevates apparent energy and delays fatigue. For awhile. In an hour or two, I find a slump as deep as the rise was high. Just like the mid-afternoon blood-sugar slump.

Now I believe that I am sleeping better with the same hours — five to six a night — am less tired during the day, and I "feel" definitely less grumpy. I haven't asked my wife or the kids if they agree with this last point. The changes came only after withdrawals were over. Of course, other stimulants still affect me: tobacco, fluorescent lighting, sugar, freeway driving, rowdy children, panic-stricken purchasing agents, etc...
Project Engineer
Mallinckrodt Sensor Systems
Ann Arbor, Mich.

Some people like a LOT of coffee. Some people like a LITTLE. Others can only take Decaf. Some can't stand any coffee at all. I never said coffee — or caffeine — was GOOD for you. — RAP

Dear Bob:
I greatly enjoyed your column on "High End" audio. I was in an automobile electronics store a while back and saw that the current fad (that's a pun) is to gold-plate everything. Yes, even the battery cable clamps that connect large lead-acid batteries to overpowered car stereo amps were gold-plated. Even the bolts that tightened the clamps were gold-plated.

Aside from the engineering questions of clamping gold surfaces against the battery's lead posts (the potential corrosion issues depending on what's under the gold), and the obvious stupidity of thinking that this will improve the stereo's sound, I think there is a deeper issue of the public's ignorance of science. When I talked with the teachers and principal at my daughter's elementary school, I was saddened to find a universal lack of interest in science, no coherent science program, and no planning for science curricula other than that the kindergarten teacher had "taken training over the summer."

At the school meeting, a parent asked about the science curriculum and the principal's response lead me to believe that she had not thought about it at all. I immediately wrote a very brief science curriculum outline and faxed it to her, and received no constructive response.

My daughter's school is one of the best in the Seattle public school system, with dedicated teachers and many interesting programs. It simply reflects the lack of public interest in scientific and critical thinking.

Engineers, scientists, designers, and technicians can contribute greatly to our society by getting involved at the elementary-school level to encourage and help teachers (who generally have no scientific training) to build fun and interesting science curricula in the public schools, so that future generations will not need to gold-pate their battery cables!
Seattle, Wash.

P.S. We hope to build a science lab at our school next year, and work on developing a fun and interesting science curriculum.

The gold-plating on a car-battery connector may be LITERALLY a good idea, because gold will not corrode. But many High-End Audio guys also do "figurative" gold-plating, and THAT I am very skeptical about. As for your volunteering to help with science in schools, I'll be surprised if you don't run into a lot of back-pressure. The teachers may see this as you ENCROACHING on their jobs — even though they may not have any clue on how to teach science themselves... Good luck. — RAP

Dear Bob:
Leave Equipment On? Yup! Usually. Bob, some leave their electronic stuff on, others shut theirs off. If I needed to heat my home most of the year, I agree with you and would leave mine on — with a screen saver. Here in Phoenix, we seldom need more heat and tend to shut stuff off more. If MIL-HDBK-217 were the gospel, wouldn't components last forever if they were off — even aluminum electrolytics?

Years ago, at GE, the feeling was that turning on a lamp, fluorescent or incandescent, shortened its life by about four hours. I can't prove it, but GE SHOULD know a lot about lamps. In mainframe computer applications, we biased those thousands of lamps so they were just below the threshold of glowing. Paying a technician to change lamps was expensive back then, too. "Experts" say flashing a lamp doesn't hurt it. But I'll bet darn few lamps get all the way back to ambient between flashes.

Does the four-hour rule apply to other stuff? Well...

Do on/off transitions hurt more than hours of being on? That "thunk" when you turn on the TV or whatever is due to HIGH inrush current. If things weren't being mechanically stressed, and things weren't moving around, why did it go "thunk?" Us electronic guys feel all failures are due to something nonelectronic — most likely mechanical.

Heating and cooling doesn't usually go "thunk," but darn few things expand/contract at the same rate... and when they're rigidly attached to one another? Bonds and welds eventually break inside of semiconductors, capacitors, connectors, and displays. Hermetic seals crack and fail, affecting chips and displays. Metals work hardens, and some of those thousands of solder joints become brittle.

If it's electronic, and gets warm when I turn it on, I leave it that way if I intend to be back within four hours or so. If I wanted the heat, I'd leave it on longer. An exception is CRTs (Cathode Ray Tubes, for you youngsters). These are "tubes" and have a finite life — especially the phosphors. My wife understands all of this and never turns the damn TV off — even in Phoenix.
Senior Engineer
Wirebenders Inc.
via e-mail

IF MIL-HDBK 217 were true, pigs could fly. The four-hour rule does not apply to light bulbs. An expert explained to me that the wear-out mechanism when a fluorescent bulb is turned on is worth four minutes. A modern incandescent bulb's degradation is around 4 to 40 ms of life every time you turn it on. Not four hours. As for ICs, I have never heard of bonds failing, or hermetic seals cracking in ordinary usage. But power devices with a soft-solder die attach will degrade their thermal impedance as a function of the number of thermal cycles and the temperatures of the cycle. And I have not heard of any particular wear-out cycle for CRTs if the cathodes and the phosphors are rested when not in use. — RAP

All for now. / Comments invited! RAP / Robert A. Pease / Engineer

Mail Stop D2597A
National Semiconductor
P.O. Box 58090
Santa Clara, CA 95052-8090

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