Peter T. Daniels ran out of electrical outlets; states rewiring entire house to be the only feasible solution.
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From: Otto Bahn on 29 Mar 2010 14:55 "Doctroid" <doctroid(a)mailinator.com> wrote >> Resistance is the opposition offered by a body or substance to the >> passage >> through it of an electric current. > > Quantitative definition, please, not just a description. Here is a > 1N4002 diode: How would you determine its resistance? Slowly increase the voltage across it until it goes "pop". It's resistance is now pretty much infinite for any value of voltage you're likely to apply. --oTTo--
From: jimp on 29 Mar 2010 15:04 In sci.physics Doctroid <doctroid(a)mailinator.com> wrote: > In article <nq6787-qkc.ln1(a)mail.specsol.com>, jimp(a)specsol.spam.sux.com > wrote: > >> All things obey Ohm's law exactly because R=V/I is the definition of >> resistance. > > In that case I hereby announce Doctroid's Law which states that > > V = D * C > > where V is the electrical potential across a device, and C is the total > mass of chocolate consumed in the past year by the person who measures > V. D is the device's Doctroidance, which is in fact defined by D = V / > C, and of course is not constant. Therefore Doctroid's law always holds > for all circumstances. > > It is also perfectly useless. As is Ohm's Law, if you consider it to be > solely a definition of resistance: it has no predictive power. Sorry, the universe, empirical data, and better than a century of electrical engineering and physics disagree with your conclusion. And obviously the phrase "characteristic curve" is meaningless to you. -- Jim Pennino Remove .spam.sux to reply.
From: Mike Barnes on 29 Mar 2010 13:58 jimp(a)specsol.spam.sux.com: >In sci.physics Mike Barnes <mikebarnes(a)bluebottle.com> wrote: >> jimp(a)specsol.spam.sux.com: >>>In sci.physics Mike Barnes <mikebarnes(a)bluebottle.com> wrote: >>>> Hatunen <hatunen(a)cox.net>: >>>>>On Sat, 27 Mar 2010 09:29:58 +0000, Mike Barnes >>>>><mikebarnes(a)bluebottle.com> wrote: >>>>> >>>>>>Hatunen <hatunen(a)cox.net>: >>>>>>>On Fri, 26 Mar 2010 08:06:21 +0000, Jonathan de Boyne Pollard >>>>>>><J.deBoynePollard-newsgroups(a)NTLWorld.COM> wrote: >>>>>>>>[...] >>>>>>>>energy being delivered, the amount of which is >>>>>>>>determined by the wattage, >>>>>>> >>>>>>>I suppose one might casually say that, but in fact the power >>>>>>>(wattage) is a function of the current and resistance, not >>>>>>>vise-versa. >>>>>> >>>>>>How so? >>>>> >>>>>Power is a result of passing a current through a resistance; >>>>>current and rsistance aren't a result of power. >>>> >>>> But it seems to me equally valid to say that current is the result of >>>> generating power in a resistance. You can't pass current without >>>> generating power, and you can't generate power without passing current. >>>> They are two sides of the same of coin. It seems wrong to me to insist >>>> (as you seemed to be doing) that one is the cause of the other. >>>> >>>> [X-posting to sci.physics with some trepidation] >>>> >>> >>>A resistance can not generate power, it can only dissipate it. >> >> You won't find me disagreeing with that (but I don't see the relevance). >> >>>The power dissipated in a resistance is a function of the resistance and >>>the externally generated voltage applied to the resistance. >> >> Ditto. > >The relevance is that the phrase "is the result of generating power in a >resistance" is nonsense. I was struggling for the proper way to express the idea, and was unhappy with "generating", but I wouldn't go so far as to call it "nonsense". What would *you* call the process of producing the energy that has to be dissipated? [Newsgroups restored. Please don't mess with the follow-ups if you want any further response.] -- Mike Barnes Cheshire, England
From: jimp on 29 Mar 2010 18:18 In sci.physics Mike Barnes <mikebarnes(a)bluebottle.com> wrote: > jimp(a)specsol.spam.sux.com: >>In sci.physics Mike Barnes <mikebarnes(a)bluebottle.com> wrote: >>> jimp(a)specsol.spam.sux.com: >>>>In sci.physics Mike Barnes <mikebarnes(a)bluebottle.com> wrote: >>>>> Hatunen <hatunen(a)cox.net>: >>>>>>On Sat, 27 Mar 2010 09:29:58 +0000, Mike Barnes >>>>>><mikebarnes(a)bluebottle.com> wrote: >>>>>> >>>>>>>Hatunen <hatunen(a)cox.net>: >>>>>>>>On Fri, 26 Mar 2010 08:06:21 +0000, Jonathan de Boyne Pollard >>>>>>>><J.deBoynePollard-newsgroups(a)NTLWorld.COM> wrote: >>>>>>>>>[...] >>>>>>>>>energy being delivered, the amount of which is >>>>>>>>>determined by the wattage, >>>>>>>> >>>>>>>>I suppose one might casually say that, but in fact the power >>>>>>>>(wattage) is a function of the current and resistance, not >>>>>>>>vise-versa. >>>>>>> >>>>>>>How so? >>>>>> >>>>>>Power is a result of passing a current through a resistance; >>>>>>current and rsistance aren't a result of power. >>>>> >>>>> But it seems to me equally valid to say that current is the result of >>>>> generating power in a resistance. You can't pass current without >>>>> generating power, and you can't generate power without passing current. >>>>> They are two sides of the same of coin. It seems wrong to me to insist >>>>> (as you seemed to be doing) that one is the cause of the other. >>>>> >>>>> [X-posting to sci.physics with some trepidation] >>>>> >>>> >>>>A resistance can not generate power, it can only dissipate it. >>> >>> You won't find me disagreeing with that (but I don't see the relevance). >>> >>>>The power dissipated in a resistance is a function of the resistance and >>>>the externally generated voltage applied to the resistance. >>> >>> Ditto. >> >>The relevance is that the phrase "is the result of generating power in a >>resistance" is nonsense. > > I was struggling for the proper way to express the idea, and was unhappy > with "generating", but I wouldn't go so far as to call it "nonsense". > What would *you* call the process of producing the energy that has to be > dissipated? To be pedantic, you can not "produce" energy other than through nuclear processes, all you can do is change its form. Energy does not "have" to be dissipated. Power and energy are two different things. The words "generate" and "dissipate" have standard meanings that can be found in a dictionary. The phrase "is the result of generating power in a resistance" is word salad. > [Newsgroups restored. Please don't mess with the follow-ups if you want > any further response.] I could care less. Crack a high school physics book. -- Jim Pennino Remove .spam.sux to reply.
From: Jerry Friedman on 29 Mar 2010 18:43
On Mar 29, 11:58 am, Mike Barnes <mikebar...(a)bluebottle.com> wrote: > j...(a)specsol.spam.sux.com: > > > > >In sci.physics Mike Barnes <mikebar...(a)bluebottle.com> wrote: > >> j...(a)specsol.spam.sux.com: > >>>In sci.physics Mike Barnes <mikebar...(a)bluebottle.com> wrote: > >>>> Hatunen <hatu...(a)cox.net>: > >>>>>On Sat, 27 Mar 2010 09:29:58 +0000, Mike Barnes > >>>>><mikebar...(a)bluebottle.com> wrote: > > >>>>>>Hatunen <hatu...(a)cox.net>: > >>>>>>>On Fri, 26 Mar 2010 08:06:21 +0000, Jonathan de Boyne Pollard > >>>>>>><J.deBoynePollard-newsgro...(a)NTLWorld.COM> wrote: > >>>>>>>>[...] > >>>>>>>>energy being delivered, the amount of which is > >>>>>>>>determined by the wattage, > > >>>>>>>I suppose one might casually say that, but in fact the power > >>>>>>>(wattage) is a function of the current and resistance, not > >>>>>>>vise-versa. > > >>>>>>How so? > > >>>>>Power is a result of passing a current through a resistance; > >>>>>current and rsistance aren't a result of power. > > >>>> But it seems to me equally valid to say that current is the result of > >>>> generating power in a resistance. You can't pass current without > >>>> generating power, and you can't generate power without passing current. > >>>> They are two sides of the same of coin. It seems wrong to me to insist > >>>> (as you seemed to be doing) that one is the cause of the other. > > >>>> [X-posting to sci.physics with some trepidation] > > >>>A resistance can not generate power, it can only dissipate it. > > >> You won't find me disagreeing with that (but I don't see the relevance). > > >>>The power dissipated in a resistance is a function of the resistance and > >>>the externally generated voltage applied to the resistance. > > >> Ditto. > > >The relevance is that the phrase "is the result of generating power in a > >resistance" is nonsense. > > I was struggling for the proper way to express the idea, and was unhappy > with "generating", but I wouldn't go so far as to call it "nonsense". > What would *you* call the process of producing the energy that has to be > dissipated? > > [Newsgroups restored. Please don't mess with the follow-ups if you want > any further response.] In my experience, "dissipating power" in a resistor means the rate of conversion of electrical energy to heat, not the rate of dissipation of heat into the environment, if that's how you're understanding it. -- Jerry Friedman |