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From: Tom Stiller on 24 Dec 2009 07:17 In article <isw-667B80.22563523122009@[216.168.3.50]>, isw <isw(a)witzend.com> wrote: > In article <C757BCBE.4E351%nicknaym@[remove_this].gmail.com>, > Nick Naym <nicknaym@[remove_this].gmail.com> wrote: > > > In article tom_stiller-2DECC3.07134423122009(a)news.individual.net, Tom > > Stiller at tom_stiller(a)yahoo.com wrote on 12/23/09 7:13 AM: > > > > > In article <michelle-371A8A.21295822122009(a)news.eternal-september.org>, > > > Michelle Steiner <michelle(a)michelle.org> wrote: > > > > > >> In article <tom_stiller-86831D.23014322122009(a)news.individual.net>, > > >> Tom Stiller <tom_stiller(a)yahoo.com> wrote: > > >> > > >>> With enough current, _any_ voltage can kill you. > > >>> > > >>> Don't forget, E=I*R. For a given resistance, you don't get either > > >>> voltage or current without the other. > > >> > > >> The human body, being mostly water with dissolved electrolytes, has a > > >> fairly low R. > > > > > > That doesn't change the fact that one can't get enough current with > > > _any_ voltage. > > It's lucky you are still alive. For extra credit, explain why power line > technicians wear all that protective gear, when they work on live > high-tension lines. > > Isaac You failed to grasp the context of my reply. A previous poster said "With enough current, _any_ voltage can kill you." ad I was simply point out that you can't get enough current with [just] _any_ voltage. It requires enough voltage to overcome the impedance presented to the source. -- Tom Stiller PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3 7BDA 71ED 6496 99C0 C7CF
From: nospam on 24 Dec 2009 12:35 In article <michelle-9CFB6A.09374424122009(a)news.eternal-september.org>, Michelle Steiner <michelle(a)michelle.org> wrote: > > > Do you think there's no difference between a 12-volt car battery and > > > eight AAA batteries wired in series? > > > > I understand about the internal impedance of batteries. > > It's not about the internal impedance of batteries; it's about the Coulumbs > stored in the batteries, or as the automotive battery makers call it, the > "cranking power". a car battery can source several *hundred* amps. an aa battery isn't going to be anywhere close to that. connect the + and - terminals of the aa batteries with a wire and you'll see a spark. the battery will probably get warm too. now try it with a car battery. actually don't do that, because it will probably melt whatever you use to connect the terminals together.
From: isw on 24 Dec 2009 12:38 In article <tom_stiller-7C6AF8.07175124122009(a)news.individual.net>, Tom Stiller <tom_stiller(a)yahoo.com> wrote: > In article <isw-667B80.22563523122009@[216.168.3.50]>, > isw <isw(a)witzend.com> wrote: > > > In article <C757BCBE.4E351%nicknaym@[remove_this].gmail.com>, > > Nick Naym <nicknaym@[remove_this].gmail.com> wrote: > > > > > In article tom_stiller-2DECC3.07134423122009(a)news.individual.net, Tom > > > Stiller at tom_stiller(a)yahoo.com wrote on 12/23/09 7:13 AM: > > > > > > > In article <michelle-371A8A.21295822122009(a)news.eternal-september.org>, > > > > Michelle Steiner <michelle(a)michelle.org> wrote: > > > > > > > >> In article <tom_stiller-86831D.23014322122009(a)news.individual.net>, > > > >> Tom Stiller <tom_stiller(a)yahoo.com> wrote: > > > >> > > > >>> With enough current, _any_ voltage can kill you. > > > >>> > > > >>> Don't forget, E=I*R. For a given resistance, you don't get either > > > >>> voltage or current without the other. > > > >> > > > >> The human body, being mostly water with dissolved electrolytes, has a > > > >> fairly low R. > > > > > > > > That doesn't change the fact that one can't get enough current with > > > > _any_ voltage. > > > > It's lucky you are still alive. For extra credit, explain why power line > > technicians wear all that protective gear, when they work on live > > high-tension lines. > > > > Isaac > > You failed to grasp the context of my reply. > > A previous poster said "With enough current, _any_ voltage can kill > you." ad I was simply point out that you can't get enough current with > [just] _any_ voltage. It requires enough voltage to overcome the > impedance presented to the source. You're right -- I understood "any voltage" to mean "no matter the" voltage (i.e. even a huge one). Isaac
From: isw on 24 Dec 2009 12:39 In article <michelle-DAA26F.08225124122009(a)news.eternal-september.org>, Michelle Steiner <michelle(a)michelle.org> wrote: > In article <tom_stiller-7C6AF8.07175124122009(a)news.individual.net>, > Tom Stiller <tom_stiller(a)yahoo.com> wrote: > > > A previous poster said "With enough current, _any_ voltage can kill > > you." ad I was simply point out that you can't get enough current with > > [just] _any_ voltage. It requires enough voltage to overcome the > > impedance presented to the source. > > Do you think there's no difference between a 12-volt car battery and eight > AAA batteries wired in series? About sixty-five pounds 8^} Isaac
From: isw on 24 Dec 2009 12:42
In article <michelle-9CFB6A.09374424122009(a)news.eternal-september.org>, Michelle Steiner <michelle(a)michelle.org> wrote: > In article <tom_stiller-F5989B.10465224122009(a)news.individual.net>, > Tom Stiller <tom_stiller(a)yahoo.com> wrote: > > > > > A previous poster said "With enough current, _any_ voltage can kill > > > > you." ad I was simply point out that you can't get enough current > > > > with [just] _any_ voltage. It requires enough voltage to overcome > > > > the impedance presented to the source. > > > > > > Do you think there's no difference between a 12-volt car battery and > > > eight AAA batteries wired in series? > > > > I understand about the internal impedance of batteries. > > It's not about the internal impedance of batteries; it's about the Coulumbs > stored in the batteries, or as the automotive battery makers call it, the > "cranking power". If the internal impedance of lead-acid cells wasn't *very* low, you could never get that "cranking current" of maybe 400-600 amperes *out* of the battery. You could still get those coulombs out, it'd just take a lot longer. Isaac |