Peter T. Daniels ran out of electrical outlets; states rewiring entire house to be the only feasible solution.
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From: Doctroid on 30 Mar 2010 14:48 In article <8sf4r5p256p95r1j553qluhns6me3pstb2(a)4ax.com>, barbara(a)bookpro.com wrote: > On Tue, 30 Mar 2010 17:05:07 -0000, jimp(a)specsol.spam.sux.com wrote: > > >From Fundementals of Physics by Halliday and Resnick: > > > >"The relationship V = i/R remains as the derfinition of the resistance of > >a conductor whether or not the conductor obeys Ohm's law." > > So the conductor might not obey Ohm's law. Some of these mokes have > been claiming that everything always obeys Ohm's law. I wonder whether he misunderstood it when Halliday and Resnick said it, or only when I did. -- Sig available on request. - Doctroid
From: David DeLaney on 30 Mar 2010 10:08 Doctroid <doctroid(a)mailinator.com> wrote: > barbara(a)bookpro.com wrote: >> jimp(a)specsol.spam.sux.com wrote: >> >From Fundementals of Physics by Halliday and Resnick: >> > >> >"The relationship V = i/R remains as the derfinition of the resistance of >> >a conductor whether or not the conductor obeys Ohm's law." >> >> So the conductor might not obey Ohm's law. Some of these mokes have >> been claiming that everything always obeys Ohm's law. > >I wonder whether he misunderstood it when Halliday and Resnick said it, >or only when I did. From what I can see, by definition, he's misunderstanding it every time. Dave "what we have here is..." DeLaney -- \/David DeLaney posting from dbd(a)vic.com "It's not the pot that grows the flower It's not the clock that slows the hour The definition's plain for anyone to see Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK> http://www.vic.com/~dbd/ - net.legends FAQ & Magic / I WUV you in all CAPS! --K.
From: David DeLaney on 30 Mar 2010 10:12 Hatunen <hatunen(a)cox.net> wrote: >"Otto Bahn" <Ladybrrane(a)GroinToHell.com> wrote: >>Out of curiosity, is the resistance of charred skin the same as >>the resistance of normal skin? > >If it's charred I would imagine it's lower. Clearly, more research is required. I have here a quantity of chicken legs, frankfurters, and scuba divers... Dave "for SCIENCE!!1!" DeLaney -- \/David DeLaney posting from dbd(a)vic.com "It's not the pot that grows the flower It's not the clock that slows the hour The definition's plain for anyone to see Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK> http://www.vic.com/~dbd/ - net.legends FAQ & Magic / I WUV you in all CAPS! --K.
From: jimp on 30 Mar 2010 15:03 In sci.physics Hatunen <hatunen(a)cox.net> wrote: > On Tue, 30 Mar 2010 10:27:52 -0400, Doctroid > <doctroid(a)mailinator.com> wrote: > >>In article <ebv3r55bt7v35nvejvpplqhr51dlpkklhi(a)4ax.com>, >> barbara(a)bookpro.com wrote: >> >>> On Tue, 30 Mar 2010 09:29:17 -0400, "J. Clarke" >>> <jclarke.usenet(a)cox.net> wrote: >>> >>> >On 3/30/2010 8:07 AM, Doctroid wrote: >>> >>> >> Anyone wishing to take this up with me further may write to me at >>> >> rsholmes at physics dot syr dot edu. >>> > >>> >Would you be kind enough to provide us an example of the equation that V >>> >and I follow for a material that does not obey ohm's law and tell us for >>> >what material that equation is valid? >>> >>> Oopsie, looks like you posted this accidentally to Usenet. >>> >>> BW >> >>'sOK, I can take this one. >> >>Zener diode: >> >>http://www.reuk.co.uk/OtherImages/current-voltage-graph-zener-diode.gif > > Ther's nothing there to indicate that Ohm's Law doesn't apply to > each point on the curve. In fact, this is a first year > engineering problem. The resistance at any point on the curve is > the inverse of the first derivative (e.g., the inverse of the > slope). This whole thing has turned into semantic quibbling. If the curve of V=IR is a straight line, the thing in question obeys Ohm's law. However, V=IR is always true by definition and is an expression of Ohm's law only if R is a constant. -- Jim Pennino Remove .spam.sux to reply.
From: David DeLaney on 30 Mar 2010 10:19
Hatunen <hatunen(a)cox.net> wrote: >dbd(a)gatekeeper.vic.com (David DeLaney) wrote: >>>> Only in materials and voltage/current ranges where Ohm's "law" is >>>> obeyed. And if damage is occurring, it probably isn't. >>> >>>Ohm's law is always obeyed in all aparatus made by humans. >> >>... ... Okay, so you're not an engineer AND are not an experimentalist. >>Meaning you're a theorist. This explains some things. >> >>(Tell the court, please, how long ago it was that humans made the first >>material that had exactly the same resistance at every interior point, and >>how to get current to go through an object in such a way as to have the same >>current density everywhere inside the object...) > >As taught in high school science classes, Ohm's Law is the >familiar V = IR. but in the real world Ohm's Law is valid for all >kinds of cases of non-constant factors, writte in lower case, v = >ir to indicate the values are non-constant. In gneral, Ohm's law >is expressed e = iz, where, as I note in another post, z is >impedance, which can be resistive or reactive and therefore >contain an imaginary component, and e is the term usually used >for "voltage". In fact, in the generic case the for Ohm's Law is >a differential equation with time dependency. Oh, certainly. Except that the law-as-given-earlier-in-the-thread was being used to find "the resistance of" a fairly large, squishy object. To do so you've got to integrate over the various internal resistances at various points weighted by the various paths the current density can be taking through said screaming object; at each of those points there'll be a value of R you could measure, if your nanabots (day-o, day-ay-ay-o ... nanobot come and I wan' go home!) were small enough, good for that particular temperature and pressure and other conditions local to that point. The original claims were more of the form that "This large squishy object has an R, and V = IR is the definition of that R, which has one value, and is a number, which you can find". Which, not so much. You're actually arguing the other side of that, I believe, and are in violent agreement with the Doctroid. The second(?)-joining perpetrator of the thread appears to be jumping on the "V=IR At Every Point So Of Course It's A Natural Law" bandwagon without fully understanding either what that means, or how this disagrees with the first perpetrator. >In other word, Ohm's Law is always true and you should avoid >making such statements unless you know what you're talking about. As long as you're doing it on a point-by-point basis and are prepared to have your overall R be a function of quite a lot of variables. Both the people getting schooled in this thread (there may be three by now, I've lost count) are missing Important Parts of that qualification in their assertions. Dave -- \/David DeLaney posting from dbd(a)vic.com "It's not the pot that grows the flower It's not the clock that slows the hour The definition's plain for anyone to see Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK> http://www.vic.com/~dbd/ - net.legends FAQ & Magic / I WUV you in all CAPS! --K. |