John Curl's Blowtorch preamplifier part II

[DF96]

As I said, I was reporting what I read somewhere. I have not done independent historical research to verify it. I do not deny that there was, and still are, some very good engineers. Blumlein and Flowers are obvious examples.

On the other hand, there is the head of the UK General Post Office (an engineer) who knew he had a problem with long telephone lines but refused to accept the solution (add inductance) offered by Oliver Heaviside because it was so counter-intuitive. He was not impressed by Heaviside's maths, so assumed he must be wrong. Heaviside took his solution to America, where people listened to him and tried it. It worked (of course, as the maths was correct) so the US had decent long distance telephone lines before the UK, even though the solution was found over here.

[Rod Coleman]

Originally Posted by DF96

On the other hand, there is the head of the UK General Post Office (an engineer) who knew he had a problem with long telephone lines but refused to accept the solution (add inductance) offered by Oliver Heaviside because it was so counter-intuitive. He was not impressed by Heaviside's maths, so assumed he must be wrong. Heaviside took his solution to America, where people listened to him and tried it. It worked (of course, as the maths was correct) so the US had decent long distance telephone lines before the UK, even though the solution was found over here.

I am not sure of the nature of your claim from this assertion. That Engineers are ignorant of mathematics, and therefore responsible for the demise of the UK's infrastructure?

If that is so, the only thing we can learn is that you have never known so much as a half-capable design engineer. I suppose that is likely enough, given the large proportion of poor examples around.

But if you meet any Real Engineers, you will find that we take mathematics seriously. Look at Blumlein's biography if you need a historical example - he prioritised mathematics above learning to read, even.

Today, many quasi-engineers hide behind SPICE and calculators and spreadsheets to attempt to tackle design problems, with uniformly poor outcomes. Their phoney nature is easy for a real engineer to spot, less easy for others.

Another consideration: before these simulating & calculating-crutches emerged, Laplace transforms were required to deal with even simple Electrical Engineering questions. I do not practice these on a daily basis, but even so, I would not call myself a professional without being quite sure about how these problems are tackled using Laplace, and what the formulations actually signify. Similarly with Fourier Transforms. Sure your PC can do all manner of things through FFTs, but do you know what the transform is actually doing? A Real Engineer must be able to say Yes.

[Bob Cordell]

Originally Posted by DF96

As I said, I was reporting what I read somewhere. I have not done independent historical research to verify it. I do not deny that there was, and still are, some very good engineers. Blumlein and Flowers are obvious examples.

On the other hand, there is the head of the UK General Post Office (an engineer) who knew he had a problem with long telephone lines but refused to accept the solution (add inductance) offered by Oliver Heaviside because it was so counter-intuitive. He was not impressed by Heaviside's maths, so assumed he must be wrong. Heaviside took his solution to America, where people listened to him and tried it. It worked (of course, as the maths was correct) so the US had decent long distance telephone lines before the UK, even though the solution was found over here.

I know of many examples of EEs that do not listen to suggestions from others, especially when they are non-intuitive, but one can always find such examples. Math and physicists are guilty of the same problem. But those were undoubtedly EEs at Bell Labs who presumably listened to Heavyside (assuming that this story is true, and that BTL guys did not come to the same conclusion first). There are plenty of EEs that listen, understand how to treat non-intuitive things, and turn them into reality.

Cheers,
Bob

[DF96]

Back in Heaviside's day, engineers (at least in the UK) were not taught as much maths as they are today. They prided themselves as being 'practical men'. Now of course there is a place for practical men - someone has to get things done. The problem is that unless they could intuitively understand something they tended to assume it must be wrong. A similar issue cropped up with modulation sidebands - many radio engineers considered sidebands to be a mathematical fiction until someone demonstrated their physical existence.

The situation is better today, but not much better. In my opinion it probably improved significantly in the 1960's and 70's, but has since declined (in the UK). Yes, engineers ought to understand Fourier and Laplace transforms and some do, but many do not. Yes, I do believe that part of the UK's relative decline in technology is due to a decline in training standards for engineers (and scientists - standards have dropped there too).

I have met and worked with some excellent engineers, so please don't think I am criticising all of them. In fact I am not criticising engineers at all, but their teachers. We have a double problem in the UK: not enough science and maths, but also not enough practical 'hands on' engineering in the courses either. Both Fourier and soldering are beyond them.

[jlsem]

But those were undoubtedly EEs at Bell Labs who presumably listened to Heavyside

That would have been Harold Arnold and Gustav Elmen of Bell Labs (Western Electric Research Laboratories at the time). Arnold was the first director of BTL and Elmen led the development of Permalloy for loading trans-Atlantic cables. Arnold was a physicist and Elmen was an EE.

John

[simon7000]

Originally Posted by scott wurcer

Not sure about that, PE has specific legal meanings like being able to sign off on drawings, etc.

Texas for one requires a PE to call yourself an engineer, as opposed to doing engineering.

A PE is required just about everywhere in the US if you do designs that concern "Life-Safety." Although that is usually structural, civil engineers (It is clear there are only un-civil engineers here) and electrical engineers doing building power designs. It can also include designers of medical equipment or even voice evacuation and notification systems.

The common use is for junior or non-PE staff to do the designs under the supervision of a PE who then is supposed to review and stamp the final drawings.

On a recent project I had to use a new structural engineer to review and approve (stamp) my attachment method drawings. My usual firm did not have enough insurance for the project size. (They would have had to pay about $100,000 more total over 10 years)

The new folks took two weeks to review my first set of drawings. They checked each and every calculation. The second set only took two days. They mentioned that on the first set everything had been over designed by a factor of 5 or more, (Safety factor is the ratio of expected load to failure point) so they felt comfortable just checking the major issues after that. A safety factor of 5 is pretty standard for stuff hung over peoples' heads except in California. There you not only allow for stuff not falling, but also that if launched into the air by an earthquake it is going up either.

Seems as bad as Japan's earthquake was their buildings stood up well, so kudos to those who do it well.

[simon7000]

Originally Posted by jlsem

That would have been Harold Arnold and Gustav Elmen of Bell Labs. Arnold was the first director of BTL and Elmen led the development of Permalloy for loading trans-Atlantic cables. They were both physicists.
John

Yes at first there were physicists, because you did not get radio engineers until after the vacuum tube was invented! The first engineers were what we now call civil engineers, starting around 1850!

Physicists of course date back to prebiblical times. I refer to the first line of Genesis for proof. It is a very exact description of the world of physics.

[jlsem]

I edited my post to show that Elmen was considered an electrical engineer (I think electronics technician was the term used at the time).

By the way if anyone is interested in the history along these lines as well as great read on the history of solid state physics I have to recommend Out of the Crystal Maze:

http://www.amazon.com/Out-Crystal-Ma...0807404&sr=8-1

John

[jneutron]

Originally Posted by DF96

Yes, I do believe that part of the UK's relative decline in technology is due to a decline in training standards for engineers

My belief is that is it a direct result of the public's lack of desire in the sciences. As such, it is engineers, physicists, scientists..all of em.

It was noted here in the US, that for the general public to understand a scientific article, the article had to be written at a 12 year old's level.

Try as I may via the tours I give, I've not been able to dispute that assertion.

It makes me unhappy.

Cheers, John

[simon7000]

GRRR! WOW! UNEXPECTED!

I just did another check on my transformer that is connected to an AC line with a DC offset of .88 volts measured by the circuit shown earlier. I used one meter on the input and another on the output. Same meters for all of the measurements.

As you can see there was some jiggle in the AC Mains so looking at the in to out ratio shows A STEADY LOSS OF OUTPUT! I would have expected an offset in the hysteresis loop but not a shift! This is a small signal transformer rated for 48 VCT out at 125ma. It is loaded by a pair of 1K resistors to the center tap. So it is a bit hotter due to the lack of load.


Input Out Ratio Ratio Diff % Out Drop
125.2 60 0.479233227 0 0
125.5 60 0.478087649 0.001145577 0.239043825
126.6 60.5 0.477883096 0.00135013 0.281727225
125.6 60 0.477707006 0.00152622 0.318471338
123.9 59.1 0.476997579 0.002235648 0.466505246
125.2 59.6 0.476038339 0.003194888 0.666666667


Again not the expected result! The transformer is actually becoming less efficient!


J.N. Do I need to explain this more clearly for the crowd here?


Note the table does not save column spacing when it goes from preparing to posting! Sorry!