Thevenin and Norton
Thevenin and Norton
(OP)
http ://www.doo nesbury.co m/strip/da ilydose/in dex.html?u c_full_dat e=20060504
http ://www.doo nesbury.co m/strip/da ilydose/in dex.html?u c_full_dat e=20060510
The question is: Am I the only one who thinks Alex, the Cornell professor and G.B. Trudeau seem to have missed the whole point of Thevenin and Norton equivalent circuits?
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The question is: Am I the only one who thinks Alex, the Cornell professor and G.B. Trudeau seem to have missed the whole point of Thevenin and Norton equivalent circuits?





RE: Thevenin and Norton
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Thevenin and Norton
In a similar vein, a DC model of a BJT is not the same or even relevant to the AC model; yet, they both purport to model the BJT.
It's a very good reminder that not all equivalents are equivalent.
TTFN
RE: Thevenin and Norton
RE: Thevenin and Norton
Unless the source impedance is either an impossible zero, or equally impossible infinity, it must then be something finite. It can then be measured, and reduced to a simple equivalent of either model.
RE: Thevenin and Norton
The Thevenin/Norton equivalents are not physical circuits. They are mathematical (or mental) representations that simplify analysis of circuits.
The idea that they are "boxes" probably stems from class-room demonstrations, like the situation in the comic strip. But, as already said, they are not. And the question can not be asked.
But, it is perfectly OK to ask the student if he can tell whether a circuit consists of a current source and a parallel resistor or if it is a voltage source and a series resistor. He shouldn't be able to tell which is what - and that demonstrates the equivalency between Thevenin and Norton.
Gunnar Englund
www.gke.org
RE: Thevenin and Norton
I would suggest Alex rephrase the question: Two black boxes are found to have identical parameters using test tools. One is known to include a current source, the other known to include a voltage source. ...
RE: Thevenin and Norton
There would be no physical way of distinguishing the difference by any testing you could possibly do across just the load terminals.
That is why the original question is meaningless. They truly are fully interchangeable equivalents, both mathematically, and in practice.
RE: Thevenin and Norton
And I thought the entire point of the exercise was to determine which college to attend.......no wonder I am going to McDonald's (see my laptop screen post)
Enjoy everyone,
Scott
In a hundred years, it isn't going to matter anyway.
RE: Thevenin and Norton
Not only will Mc Donald's hamburger university give you a well rounded education, you can also get a good square meal.
http://en.wikipedia.org/wiki/Hamburger_University
RE: Thevenin and Norton
Now I wonder what happened to my original post?
I think I am losing my mind!!!!!
Scott
In a hundred years, it isn't going to matter anyway.
RE: Thevenin and Norton
RE: Thevenin and Norton
And was your answer an acceptible one?
Scott
In a hundred years, it isn't going to matter anyway.
RE: Thevenin and Norton
RE: Thevenin and Norton
RE: Thevenin and Norton
I agree with Warpspeed. And to all, my original post about my laptop LCD was deemed "inappropriate for this forum" and has been removed. When they answer me, I will re-word it without the humor and post it again.
Thanks,
Scott
In a hundred years, it isn't going to matter anyway.
RE: Thevenin and Norton
RE: Thevenin and Norton
If the candidate truly knows his stuff, he is not going to be rattled by something like that.
The last job interview I had there were two interviewers, and it lasted NINE HOURS, It was pitch dark when I finally emerged. But I did get the job, and they paid me for the day, hehehe. That was with a telecommunications company in Melbourne.
RE: Thevenin and Norton
This a continuing problem that occurs when management dictates that prospective employees transgress through HR. Lower mgt. proposes the questions, and then the results are relayed back to the "hiring manager." That's my life anyway. Multiple interviews with the knowlegable persons involved could (and should) prevent this problem. I personally don't see this happenning any time soon.
Thanks,
Scott
In a hundred years, it isn't going to matter anyway.
RE: Thevenin and Norton
But in smaller companies, and privately owned businesses, the interviewer is most likely to be the chief engineer.
RE: Thevenin and Norton
Is it any more irrelevant than figuring out the threshold voltage of a TTL input? Which the applicant failed to answer THREE times, where he was shown the answer after both the first and second times?
TTFN
RE: Thevenin and Norton
After learning the Thevenin and Norton stuff I have never ever used it. Pish-shaw!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Thevenin and Norton
Where you could get 25% just by chance, I found a score of 35% was a good candidate. Some people ran out of the room. The only one that ever passed it said he wouldn't work at such an idiotic place. I had to reduce the test to 4 questions because they were taking close to an hour to answer 20 simple questions!
RE: Thevenin and Norton
I once took a test for the electrician's union placement. I aced the math and was in the top 5% for the the ridiculous "draw lines between the lines" of hundreds of concentric circles with both hands at the same time. Some sort of mind numbing dexterity test. Then I got to the verbal. After we all laughed about the my then recent news worthy arrest for driving around my town and over some hundred foot trestles on the railroad tracks they asked me how badly I wanted to be an electrician. I said I wanted to actually be an Electrical Engineer.. That was a conversation stopper. Hahaha . We all decided I shouldn't bother with the electrician path.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Thevenin and Norton
RE: Thevenin and Norton
I felt really bad, until I went back to my dorm and asked many of peers who were all as stumped as I had been.
RE: Thevenin and Norton
By the way, it might confound the line-cord heat analyzers if they were not allowed to "peek" at the two output terminals (fair's fair!) How? Easy. If the two ouput terminals were shorted (the dual of the open circuited case) the Norton Equivalent box would remain cool as a cucumber....