Doesn't anyone begin to wonder; "Maybe there are anomalies in our life"?
Mabey ohm's law is defective, or maybe it isn't?

 

Yes, I hope to get off to sleep tonite

 

...10v power supply ...
...exactly 2mA

total resistance will be R = V/I = 10/2e-3 = 5000 ohms (so the 9300 ohm resistor can no longer exist - or the current would still be 1mA)

... diode or no diode, linear or not, I am still using Ohm's law ?

REMEMBER I said instantaneous ?

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I need a memory upgrade ...
My head is full !

 

Well, okay. Even though I think these statements in Art of Electronics are nonsense, I will concede that you may be able to counter every reference I can provide and stalemate is the potential outcome. And since I will accept only text references (or perhaps the statement of someone with supreme credibility, like the head electrical professor of some universities) there is nothing more I can offer to bend you to my will. So while I do not agree, I will argue no longer.

Thanks, that was fun.

PS: to MARKS256. No, Ohm's law is not defective. I've used it for every kind of device for 33 years and it has never failed me. So don't worry, I does indeed equal E/R.

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RadioRon

 

I never said it was. I just said there is that possablity. It could also be human error....

Edit: Tried to fix some spelling, but it, once again, didin't help....

 

1.possibility
2.didn't

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i² = j² = k² = ijk = -1

 

Just to drag the debate a little further, a couple of extracts from:

http://en.wikipedia.org/wiki/Ohm's_law

These infer that Ohms law should only be applied to devices with linear V/I characteristics.

JimB

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Experience is directly proportional to the value of the equipment ruined.

 

Must have the last word, eh? Well, despite the fact that I don't accept anything posted on the internet (i.e. Wikipedia doesn't count) I read the article anyway.

I can't help but think that this difference of opinion is like arguing about the most correct form of a word or phrase in English. Words and grammar evolve and whether we like it or not, common usage of a thing often, after a time, dictates what the thing is no matter what the original inventor intended. We see every day that new words are invented and old words are perverted by the democratic masses and while some of these things happen by dragging linguists kicking and screaming to the alter of practicality, at some point in history the new form becomes "correct". This is how we get saddled with words like "parenting" for example. This is true of any language, and I think this is true of poor old Georg Ohm's old Law. It may originally have been meant to apply only to circuits with elements who's V/I behavior was constant for any I, but that was then and this is now. In any case, it doesn't matter because the relationship I=V/R is universally taught and applies to differential resistance just as well as ohmic resistance. In my text books and my experience, this relationship is commonly called Ohm's Law and that is the modern fact of life. If you want to be a purist and a Luddite, like our Wikipedia authors seem to be, then OK, Ohm's Law is the special case where I=V/R but only when R is not a function of I. But the rest of us who speak modern English, not the English common in 1840, accept the modern version, I=V/R (period) and we feel no compunction to calling this Ohm's Law. Why shouldn't we accept it, as it is the more general case and works no matter what the material causing the resistance. In other words, who really cares if the original Ohm's law only applied to constant R when in fact I=V/R works differentially too. I think Georg would have been proud that the general case is attributed to him, even though this was not his original claim.

glad to be here
RR

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RadioRon