Ohm's Law Problem

Perhaps I wasn't very clear. My example was _abstractly_ drawn. I was speaking with an allegory here.

The point was allegorical. And missed, I see. My fault. And as I said, this is getting far afield. So I'll leave it for the book I recommended to paint better than I have.

You didn't get the allegory, it seems, so let's 'hold off' on a response from me on this.

Of course!! Engineers must _design_ in the here-and-now with whatever is available for the task at hand. I certainly wasn't arguing there.

I think this is why there is art _and_ science in engineering.

If I had to put a cap on what you are saying, I'd simply say that you should choose the best at hand. If there is very good, quantitatively predictive theory floating around for something, use it. If not, use what you have. Trial and error certainly has a place. So does an instinct that is developed through what you suggested, "experiment, experiment and experiment."

Hehe. Me, too. However, I think that book is extremely readable and enjoyable in each and every paragraph. You'll find it no trouble at all. And cheap, besides. Why not expose yourself to something merely on a lark once in a while. Might expand a horizon and find something fun you didn't realize was in you. ;)

Jon

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Ok, but we spend the evenings with bible reading, card games and (full confession here) lately some TV. We discovered a secondary digital channel which carries "THIS-TV". Tons of documentaries, old movies, westerns and so on.

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Regards, Joerg

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Krautkraemer was located pretty close to us, I used to work in Solingen. But it seems you do not know much about medical ultrasound. It's a heck of a lot more complicated than NDT and the competition is very fierce.

Did you ever design parts of something like this?

I did. Actually I ran the imaging division when it was EndoSonics and they don't let you do that with a limited experience :-)

Hint: There are 64 transducer elements in the tip, plus five integrated circuits. Oh, and the machine that goes with it has full color flow capabilities despite the fact that the blood flow is perpendicular to the beam direction. Many groups tried but we never had any competition in electronic IVUS, they still don't. Oh, and HP threw in the towel and shut down their IVUS business. That should give you a taste of how difficult this stuff is.

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Oh, my, Jörg! Cut a TV show or two!! The book requires maybe three hours. It's not a bible, or something.

By the way, I've spent many thousands of hours reading the bible -- and even doing my own translations of parts of it, from source materials and references. I keep shelves full of various books and parallels (you might know what these are, don't know), as well. A couple of years of university level theology training does that to one, I suppose. What I'm asking is _nothing_ like that! It's easy reading.

And card games appeared to also be the usual fare for us Swedish family types, though I've long since dropped most of that habit. ;)

But every evening doing bible reading??!!?! if you are spending that kind of time, I highly highly recommend taking some serious, high quality, university level coursework. You really need to be able to know where to go to get the raw materials and do some of your own work in finding out exactly what source materials exist (fragments only, in many cases, if you use the earliest stuff), how they vary each from another (and they do, in some cases a lot), and gain some knowledge about _how_ people wrote and thought about things back then so you can place what you see into some cultural context, as well. Cripes, if you are working that hard, you should get a leg up on the more academic side of this. You've obviously got the energy and interest for it.

Jon

But it's hard to forego a great western :-)

Well, I got to be honest here. I don't have all that much fun reading the more philosophical texts.

The theology training I do not have, sometimes I wish I did. But got to retire first ;-)

One of our house rules: We never play for money, with anyone. Just for fun. In the same way we never visit casinos.

Interest, yes, but not sure about the energy. The author of "40 Days of Purpose" wrote something that kept ringing in my mind: "You can do the umpteenth bible study but at some point you've got to take what you know and get out there with it, and do stuff", or something like that.

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Remember the old OH2AM team in many contests decades ago?

I have seen the phenomenon with 807, 813, 6146, EL 500, EL 509 and some TV line output tubes with US markings (6LQ6 & co).

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Tauno Voipio
tauno voipio (at) iki fi

I won't dive into any project unless I can hash out the details on the computer first. The wife wised up when I tried to apply that to the lawn mowing. My newest excuse is that I don't have the right tool, and I don't want to buy one becuase I'm waiting for the newest model that comes with a remote. We'll see how long this lasts.

Not sure, last time I participated in contests was in the late 70's.

Even 807? Yikes. I've mostly seen it with PL509 tubes and maybe the occasional 6KD6.

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Ah. Well, it certainly won't help you build the next thing. ;) I try and keep fingers on both sides. For example, I both _designed_ the entire home for my son, doing all of the engineering calculations required, as well as personally dug the foundation (alone), laid the foundation boards and placed the rebar, added rebar clamps, built a cubic foot wooden box to hold and measure gravel and cement, and mixed and poured it. I think _all_ is important, theory _and_ practice.

hehe. Well, I have a million recommendations there, too. There's a great web site now that actually places up the photographs of various fragments of source materials, for example. Lots to study, there. I can assure you of one thing... if and when you ever get around to doing that work for a while, your entire perspective WILL change. No question. I don't mean to suggest it will change your beliefs -- my favorite teacher of theology was a Catholic nun and she would certainly run rings around me on this subject. So you will hold your beliefs, likely. But I can assure you that some facets of how you think about it will markedly change from the experience.

Hehe. I don't remember betting on canasta around here. :)

Well, don't do the umpteenth. Just the first, second, and third. If you are arguing that ONE BOOK is a dedication of your life, well.... I just don't know what to say to that.

Jon

I guess just about every son would want a dad like that :-)

It always amazes me when we ask our pastor a tough question and then he says "I'll better go all the way back to the source material on that one". Even between 2-3 modern language translations there can be serious differences and consequently misunderstandings.

A lot of people form little private clubs and count rommee points and all that. After a couple years there's often enough in the kitty for a little bowling trip with the whole group. Not much money involved, but we like to keep it clean, no money. Just the fun part.

Done.

I've read a few more than just one :-)

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hehe. I took it on for the _same_ reasons that I stated in this group on the Vbe multiplier: "I'd rather _keep_ the money and _keep_ the education for myself. That way it pays off, again and again." It was for _my_ benefit, as well as his. Saved a hell of a lot of money, too!

Yes! But I have learned that if I want to find out for myself and not rely upon the interpretation of others, I have to go back to copies of the source materials (and as much of it as possible.) For example, did you know that the very earliest pieces of the new testament date to about 125 AD? Fragments from Matthew held, last I heard, at Oxford's Magdalen College. Bits from chapter 26, for example. Just a few words here and there.

Jon

The trick is knowing when it's cheaper overall to just purchase a product or service. :-) In personal life, for most of us this choice is clear-cut (it's only folks like Warren Buffet who would very likely be losing money if they chose to build their own home), whereas with businesses it seems common when small businesses struggle to grow beyond a certain threshold due to the founders being unwilling to risk others starting to make some of the big decisions... or somewhat alternatively, trying to develop all their skills internally when it'd be much cheaper and faster to hire a good consultant.

[...]

Some of its history has even made in into wikipedia:

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Regards, Joerg

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=20

=20

There are people finishing their BS in their 50s and later. I was over =

40.=20 The bottom line is never quit, never say die. And then one day you = graduate. Trust me that can be a delicious moment. Especially if there are/were=20 family/friends that did not believe you could make it.

Only in parts of Europe. :)

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Greed is the root of all eBay.

Oh my dear, I don't like to brag about my work. This US flaw detector for example still in use after 20+ years.

Thousands of students must have pressed the buttons... In the first place it was a joint effort of all 14 design engineers and 6 softies and my colleagues were very capable and we helped each other. Then in 1986 when we did this it was challenging to make a portable and reliable instrument with digital control. I was just doing the analog front end and helped with the deflection amp for the CRT (no LCDs yet). I designed and prototyped a couple of hybrids for this, one is the 2"x1" input amp. Almost everything else is surface mount. And I can say *everybodies* life depended on it many times. Die Bahn and British Rail testing steel axles or all airplane companies, nuclear reactors, space shuttle, mines used and still use it. It is working at -20°C in Siberia with the specified accuracy as well as at +80°. And the company regained the 85% world market share it had lost before and it was sold 5 times more than projected more than 20000 units ... And again I was just part of the team tho the only consultant and without the help of Dr. Volkmann who came from R&S, I wouldn't have been able to succeed at all :-( ciao Ban

I don't either (well, ok, sometimes ...), just wanted to show that your ad hominem statement about limited experience is plain wrong. I am doing this since 1986, to be exact.

Ah, hybrids. We probably did ours at around the same time. Mine were then produced at Philips Krefeld and also Turck in Halver. I had a lot of fun designing hybrids but unfortunately that era has ended :-(

Ok, nice, and I don't want to belittle this technology in any way. It is needed and will ensure safe operation of public transportation and other gear, as you wrote. But technologically it is a very different ballgame versus medical ultrasound. It looks like a classic A-mode system where the transducer has only one element. Or maybe several in annular array configuration for focus.

A-mode is gone from medical, since the 70's. State-of-the-art is now beamforming with 64 or more channels running at the same time. succeed at all :-(

Same here, there have to be real scientists involved and those are often Ph.D. with a serious physics background. Same on the project I am working on today. All I wanted to say is that there always was and still is stuff in ultrasound that's next to impossible to grasp from a science or simulator point of view. Even where it is, when a sim on the hottest screaming machine takes weeks you have to cut to the chase at some point, so you get to market in time. This is also why a lot of recipes (filler, backing material, acoustic lens, and so on) are closely guarded trade secrets. You won't find any info about this stuff here at the office, it's all destroyed the minute I don't need it anymore, only the respective client keeps it.

--
Regards, Joerg

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