Engineers Must Pay

[The New Steve H]

I am getting pains in my skull from studying electronics. I cannot get used to the way engineers slop units around. The outline I'm using will divide volts by amps or whatever and give a result which is a pure number, or they'll use the symbol "I" to mean a pure number, and I just want to smack whoever wrote it.

I demand that all engineers, worldwide, cut the crap and start keeping track of units.

On the up side, I managed to get Mathcad working, in spite of PTC's dogged efforts to make it incompatible with all operating systems, hardware, and applications.

I realize this has nothing to do with amplifiers, but I had to say something or my head would have exploded.

[ampdoc1]

Don't know what you mean by a pure number but ohm's law is typically defined as V(volts)= I(current) x R(resistance). Substituting the values for any two of the units will give you the third.

a'doc

[John_P_WI]

Hmmm, as an engineer for more than half of my life I don't see the problem

We usually carry the units through... something that I had a hard time teaching my kids when they were learning algebra etc.

[The New Steve H]

This is the kind of thing that only matters to physicists and math nerds. A "pure number" means a number like e or pi, which has no units. For example, if I use the term "5V," it's not a pure number, because it has the unit "volt" attached.

"Dimensional analysis" refers to checking the units used in equations to make sure your results make sense. For example, if you're trying to find out how much kinetic energy a system has, and your answer comes out in gallons, you've screwed up somewhere.

If you're used to keeping track of units, it's really irritating to deal with texts where they get ignored and misused. When I was a physics TA, I used to hammer my pre-meds all the time about keeping units straight, and now I'm dealing with a book written by a professional engineer which basically poops on everything I said.

[XgamerGt03]

If you looked at my work all the way from freshman year till now working in industry you'll see everything has units associated with it.

I don't even plug in numbers until I've solved an equation for the variable I want and make sure that the units make sense.

I'm guessing by pure number you mean someone saying

5 Volts / 1 Amp = 5 and not
5 Volts / 1 Amp = 5 ohms

[ChrisM]

If you looked at my work all the way from freshman year till now working in industry you'll see everything has units associated with it.

I don't even plug in numbers until I've solved an equation for the variable I want and make sure that the units make sense.

I'm guessing by pure number you mean someone saying

5 Volts / 1 Amp = 5 and not
5 Volts / 1 Amp = 5 ohms

Big +1!!!

Dimensional analysis has saved my ass big time on countless midterms and finals so far going through my EE degree.

[The New Steve H]

Why do I keep getting the answer "40 ounces"?

[surfsup]

OldE baby

[vibratoking]

Dude, settle down.

In my experience, we engineers always acount for the units.

What book are we talking about?

The people at Mathsoft care more about the licensing than the actual product. That's why I quit using it.

[VacuumVoodoo]

I don't even plug in numbers until I've solved an equation for the variable I want and make sure that the units make sense.

This alone qualifies you for a hefty salary raise. Tell your boss I said so.

[Zippy]

I am getting pains in my skull from studying electronics. I cannot get used to the way engineers slop units around.

If you've got a beef with a single book, how 'bout leveling your damnation at that person instead of calling out all the engineers in the world?

That's pretty sloppy too, wouldn't you agree?

FWIW, I don't recall experiencing your definition of "pure" numbers. Where did you encounter that terminology? "Dimensionless", yes, but I haven't heard "pure" in that context.

BTW, I found it useful, when encountering a text that I didn't like, to get complementary books in the area of study. I've quite a minor library of thermodynamics and quantum mechanics - neither was my favorite but having several books for each of several classes really helped sort things out for me.

[John_P_WI]

Ah, it is all in fun. Don't hammer on Steve too much, we all have things that piss us off - some easier than others.... The good point is that he is trying to learn. Agreed, supplemental books / learning materials etc are always good.

As far as units go, the answer I prefer is 12 oz, as in 12 oz / bottle of Sam Adams Boston lager. Note - liquid or fluid ounces, as 128 oz / gal

[The New Steve H]

how 'bout leveling your damnation at that person instead of calling out all the engineers in the world?

No, that won't provide the desired level of venting. All must pay.

I didn't make up the term "pure number," believe it or not. I don't know if it's the best term to use, and I am not going to burn up Google finding out, because no one cares. After a 15-year layoff, I'm happy I know anything at all.

Someone asked what I'm using. Basic Circuit Analysis, by John O'Malley.

[The New Steve H]

Think of my complaint as a reverse class-action. Instead of ten million people suing one company, one guy persecutes the entire race of engineers. Including guys who drive trains.

[statorvane]

I didn't make up the term "pure number," believe it or not.

I think most engineers, chemists, physicists would refer to these as dimensionless.

Come on, get jiggy wit' it and join the engineering ranks! Then you can complain about the beancounters!