Peter T. Daniels ran out of electrical outlets; states rewiring entire house to be the only feasible solution.
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From: barbara on 30 Mar 2010 08:17 On Tue, 30 Mar 2010 18:26:04 +1200, "PaulJK" <paul.kriha(a)paradise.net.nz> wrote: >A homework for Doctroid and P.Moylan >http://www.allaboutcircuits.com/worksheets/diode1.html > >just trying to help you to stop embarrassing yourself with >high school physics. P'raps you should ask Doctroid what he is a doctroid of. BW
From: Doctroid on 30 Mar 2010 08:48 In article <7uq3r59afg17p63gsvitp4qbm6uh3032f8(a)4ax.com>, barbara(a)bookpro.com wrote: > On Tue, 30 Mar 2010 18:26:04 +1200, "PaulJK" > <paul.kriha(a)paradise.net.nz> wrote: > > >A homework for Doctroid and P.Moylan > >http://www.allaboutcircuits.com/worksheets/diode1.html > > > >just trying to help you to stop embarrassing yourself with > >high school physics. > > P'raps you should ask Doctroid what he is a doctroid of. > > BW See, the thing about high school physics is, it's taught by high school teachers out of high school textbooks to high school students. High school physics teachers usually do not have advanced training in physics. Often neither do the authors of high school physics textbooks. Even when they do, they recognize the necessity of presenting a simplified picture to high school students, who are not ready for differential equations, surface integrals, and deep questions about the meaning of physical law. So what gets taught is "Ohm's law is V = IR". The ones who go on to earn degrees in physics are taught there's more to it than that. (And some of them learn it.) The ones who major in English Lit or Business or Electrical Engineering? Might not. -- Sig available on request. - Doctroid
From: barbara on 30 Mar 2010 09:33 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
From: Doctroid on 30 Mar 2010 10:27 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 -- Sig available on request. - Doctroid
From: Otto Bahn on 30 Mar 2010 10:29
"Peter Moylan" <gro.nalyomp(a)retep> wrote >>>>>> Voltage and current are proportional to each other. >>>>>> It is therefore sufficient to say that damage is proportional >>>>>> to one of them. >>>>> 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. >>>> >>> Except when it isn't - which is most of the time. >>> >>> It's true that a great many resistors are nearly linear, i.e. they can >>> be said to obey Ohm's law to a reasonable degree of accuracy, provided >>> that you don't go beyond their design limits. >>> >>> It's equally true that some resistive devices are *deliberately* made to >>> be nonlinear. A semiconductor diode, for example, would be totally >>> useless if it obeyed Ohm's law. >> >> I see you didn't have Ohm's law in your high school? > > No, I didn't. I studied it as a university student. Subsequently, I > taught circuit theory at both the elementary and advanced levels. By the > time I retired, I was an Associate Professor of Electrical Engineering. > If you're trying to cast doubt on my credentials, you'll need to insult > my university rather than my high school. Out of curiosity, is the resistance of charred skin the same as the resistance of normal skin? --oTTo-- |