Talk:Coulomb
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Does coulomb imply positive or negative charge? Since the ampere per second is conventional current, would it technically be 6.24×1018 times the charge on a proton? - Omegatron 16:36, May 26, 2004 (UTC)
- I think you're probably right. However, I think it probably also makes sense to say "1 coulomb of electrons", knowing that this is the same as -1 coulomb of conventional charge. -- Anon
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- Er ... I think "does coulomb imply positive or negative charge?" is as meaningful a question as is "does meter imply positive or negative distance?" (or rather, displacement, so that we can actually allow negative values). A unit in itself has no sense of direction, positive or otherwise; it's just a measure of the magnitude.
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[edit] put number of electrons / coulomb on top
thats what people look for when they get to this page, now they first have to skim through not so important numbers (Explanation, Faraday...) before they get to number of eletrons —Preceding unsigned comment added by 209.221.240.47 (talk) 18:52, 30 October 2007 (UTC)
[edit] no need for a list of binary prefixes. avogadro's number is a common misconception
thank you but i don't understand!
Discussion moved to Talk:Units of measurement
[edit] Kilogram
<-n00b says : . . . . Kilogram ?!? Please clarify how the kilogram applies.
- I don't see how the kilogram note is relevant to this article. Being that it lacks an explanation, it's just an odd little statement.
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- I see how one can make that statement, but I'm not sure how to fit it into an encyclopedic article, not a physics homework. Anyways, this is how: the definition of ampere states, 1 A is the current such that if 2 parallel wires (at distance 1 m) have 1 A through it, there will be 2e-7 N/m of force on wires. Defining C on its own gives an alternate definition of ampere as 1 C/s, and once ampere is defined that way, we can define newton in terms of ampere, and since newton = m*kg*m/s^2, now we can define kg in terms of newton .... which is defined in terms of ampere and meter, which is defined in terms of coulomb and meter and second.
- Interesting, but why mention the kg here at all? —Preceding unsigned comment added by 207.189.230.42 (talk) 08:50, 28 October 2007 (UTC)
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- Presently, the kilogram is an artifact, there is a platinum iridium cylinder in France somewheres, and the kilogram is defined as the amount of mass equal to the mass of that cylinder. obviously, that's kind of untidy, physicists would much rather have the kilogram based on a universal constant. personally, I can't see why they don't just count out one thousand moles of protons. —Preceding unsigned comment added by 207.216.24.138 (talk) 08:00, 3 December 2007 (UTC)
- Yes, but the article is supposed to be about the coulomb. 207.189.230.42 (talk) 09:09, 15 December 2007 (UTC)
- I agree, the kilogram paragraph is confusing.
- It is given top-level "explanation status", but it is really an esoteric proposal that has apparently not been adopted by the physics community and doesn't make anything clearer to the novice. Could this be put at the end?
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- I came to this page looking for an explanation and was hoping to find something about the idea that a charge can be accumulated in a space or device (e.g. capacitor), and just how large 1 coulomb of charge is (e.g. a 10,000 uF capacitor charged to 100V stores 1 Coulomb). And intuitively, why are Coulombs of charge, which can be stored in a capacitor, different from Joules of energy, which can also be stored in a capacitor (or battery)? -Paul —Preceding unsigned comment added by 68.122.32.141 (talk) 15:53, 13 February 2008 (UTC)
[edit] Historical Note re derived unit
"The Ampere is in fact a derived unit..." but not according to the Wikipedia entry for Ampere, where it says, "Because it is a base unit, the definition of the ampere is not tied to any other electrical unit."
Given the definition for the Ampere as given in the Ampere entry, I'm inclined to believe that the Ampere is in fact the base unit and the Coulomb is the derived unit, despite the relationship 1 A = 1 C/s.
- Correct. The current SI standard defines the ampere as a base unit, for practical reasons. (It is more intuitive to think of the charge on one electron as fundamental unit on which to base the definition of the Coulomb and then base the Ampere upon the Coulomb, but that's not how things are defined in current SI.)
- I am suspicious of the article section: "The ampere was historically a derived unit - being defined as 1 coulomb per second. Therefore the coulomb, rather than the ampere was the SI base electrical unit," because what I have read of the history of electrical units did not say that the ampere was figured from coulombs. Here are pages about the history of electrical units:
- http://alpha.montclair.edu/~kowalskiL/SI/SI_PAGE.HTML
If no one has any good reference that contradicts those references, I shall in time remove or replace the sentences. Nicknicknickandnick 08:54, 28 October 2007 (UTC)
[edit] Constant vandalism
Oh grow up! N^O^el (talk) 06:45, 5 March 2008 (UTC)
[edit] Real-world example
It would be nice to have a real-world explanation of how much energy 1 Coulomb is.N^O^el (talk) 06:47, 5 March 2008 (UTC)
Yes indeed it would be an awesome idea --can some expert educated us. --69.235.4.174 (talk) 08:47, 31 May 2008 (UTC)
[edit] Better Definition?
According to Teach Yourself Electricity and Electronics Third Ed 1 coulomb = ~6.24 x 1018 electrons or holes. A current of 1 coulomb/1 sec = 1 amp. I find this definition a lot easier than the current one though it seems less precise. Could someone with more knowledge edit this page to include the definition that I've included, or explain why this definition was not included?. --69.235.4.174 (talk) 08:47, 31 May 2008 (UTC)
