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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)
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)
thank you but i don't understand!
Discussion moved to Talk:Units of measurement
<-n00b says : . . . . Kilogram ?!? Please clarify how the kilogram applies.
"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.
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)
I removed the reference in the article. I wasn't logged in, so the edit is under an IP address. I thought I'd document my findings, and why I removed it.
The first definition of the coulomb was by the 1st international Congress of Electrical Engineers in 1881, and clearly indicates that the coulomb is derived from the ampere. Resolution 6 of that Congress states: "A quantity of electricity given by ampere in a second is to be called a coulomb." - source IEC The ampere was derived from the volt and ohm, but it was NOT derived from the coulomb.
"The international ampere adopted at a meeting of the British Association in Edinburgh (1892) was the current that would deposit silver from a silver nitrate solution at a rate of 0.001118 g/s under specified conditions, using a silver “voltameter”" - source NIST This is the first reference I could find where the ampere first becomes a base electrical unit (i.e. defined in terms of mass and time, but not in terms of other electrical units).
The 9th CGPM (1948) adopted the ampere for the unit of electric current, following a definition proposed by the CIPM (1946, Resolution 2), the equivalent definition which is used in the modern SI: "The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 x 10–7 newton per metre of length."source BIPM
I can find no authoritative reference for the coulomb ever having been considered a base unit. (the reference in the article was to a $$ journal article, written by someone from Montclair State College).
Msauve ( talk) 23:10, 5 April 2009 (UTC)
The coulomb is not an SI unit! There are only 7 SI units, ( http://en.wikipedia.org/wiki/International_System_of_Units) and the Ampere is one of them, not coulomb. Someone please change the first sentance of this article which describes the coulomb as the SI unit for electric charge.
Oh grow up! N^O^el ( talk) 06:45, 5 March 2008 (UTC)
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)
I added an "everyday charges" section. -- Steve ( talk) 21:31, 29 January 2011 (UTC)
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)
I was always taught that one coulomb (6.24 x 10 to the 18th) is the approximate number of electrons that pass a specific point per second at one volt and one amp. — Preceding unsigned comment added by 198.45.149.17 ( talk) 00:46, 3 February 2015 (UTC)
I would like to propose adding the Q=It equation found on the Ampere page on this page, as Q also represents Coulombs. I feel that this would help clear some confusion I personally experienced initially, which was why there where two different symbols (C and Q) for the coulomb. Or is there some reason why its not there? 209.129.16.5 ( talk) 04:17, 3 February 2009 (UTC)
Why are zeptocoulomb (10^-21) and yoctocoulomb (10^-24) listed when a single electron has a charge of about 1.602 x 10^-19 coulombs and the smallest quark charge is 1/3 of this? Is there something I'm missing here? -- B.D.Mills ( T, C) 10:37, 2 March 2009 (UTC)
I agree with both of you - I'm deleting zeptocoulomb and yoctocoulomb. If somebody has a reference for those actually being used, feel free to put them back in. Enon ( talk) 21:25, 17 May 2010 (UTC)
The table is automatically generated by a template, Template:SI multiples which made it difficult to edit. The best I could do was to note zeptocoulomb and yoctocoulomb as "not used". A note on when fractions of a esu are meaningful ( fractional quantum hall effect, quarks etc. might be helpful or it might be off-topic. Enon ( talk) 22:10, 17 May 2010 (UTC)
Zeptocoulomb is used in the article on Zepto- [ [1]]. Xakepxakep ( talk) 20:13, 18 March 2011 (UTC)
Yeah I saw that too, that yoctocoulomb etc. are way below the physically smallest possible charge, so I got a smile out of it. But I think it's ok since we often describe charge states by differential equations, i.e. we talk about charge in terms of the continuum limit. It's like the smallest amount of US money is 1 cent, but it's still perfectly fine to do a financial calculation in nanodollars, or (in practice) in floating point arithmetic on a computer. The real silliness is that those far-out prefixes exist at all, and I doubt they're used much in practice. We similarly might deal with numbers on the scale of a vigintillion, but we'd usually describe them with scientific notation instead of by that name. There don't even seem to be names for number sizes between the vigintillion and the centillion. 173.228.123.121 ( talk) 23:05, 5 March 2018 (UTC)
In principle, the coulomb could be defined in terms of the charge of an electron or elementary charge. ... . A coulomb is then equal to exactly 6.241 509 629 152 65 × 1018 elementary charges.
Elementary_charge It has a measured value of approximately 1.602176487(40)×10−19 coulombs.[2]
???????????// —Preceding unsigned comment added by 123.24.118.155 ( talk) 03:07, 18 November 2009 (UTC)
"-6.24151×1018 electrons"
Since it makes no sense to have a negative number of electrons, and units are typically treated as magnitudes, not vectors, shouldn't this be positive? 71.55.0.14 ( talk) 05:34, 29 January 2011 (UTC)
It does actually make sense to have a negative number of electrons. In semi-conductor talk, these are holes. If you have a material, and you remove 10 electrons, you get charge on that material. That'd be a value of -10 electrons, or 10 holes. -John —Preceding unsigned comment added by 50.88.51.181 ( talk) 21:31, 11 May 2011 (UTC)
Hi Wtshymanski,
I made this edit, which you undid here. The explanation was "not the way the coulomb is defined". Can you say more specifically what it is that I wrote that is wrong? Are you disagreeing with my "Definition" section, or my "Relation to elementary charge and "conventional Coulomb"" section, or both? Whichever it is I will be happy to supply references, I don't believe I wrote anything that isn't standard and universally accepted.
Also, you put in a template, "This section does not cite any references or sources," in a section that cites two sources! In the future I suggest the {{ citation needed}} template would be a better choice. Or do you think the current citations are invalid? I can see that the battery capacity claim should have a citation, but I don't think the Coulomb's law claim needs one, it's a straightforward calculation that anyone can check. (BTW right now that example is in the article twice! You restored it without re-deleting it from the other place.) -- Steve ( talk) 22:43, 29 January 2011 (UTC)
UPDATE: I restored my version, now with a footnote source for almost every sentence I added. If you think something is incorrect or unclear please let me know. -- Steve ( talk) 19:05, 30 January 2011 (UTC)
Something is amiss and entirely confusing. Comparing the Coulomb article: "1C = 1A x 1s" with the Ampere article: "one coulomb per second constituting one ampere" leads me to believe, substituting for 1A, that 1C = (1C x 1s) x 1s which leads to my confusion.
As I understand it by reviewing information in the Coulomb and Electric Current articles: a Coulomb is the charge of ~ 6 x 10^18 electrons or protons and an Ampere is the current of that charge flowing for one second.
From the point of view of someone trying to learn and understand this, I'm utterly confused and/or thinking an error could have been made. If none of the articles are technically wrong, having such seemingly contradictory information in the lead paragraph should either be briefly explained or deferred to the body of the article.
I'm not qualified to make or suggest what the changes should be. From my point of view, it's confusing and frustrating when you're learning and something is self-defined. I may be wrong if I arrived at 1C = (1C x 1s) x 1s but I wish it were clearer instead of seeming similar to reading "canine" defined as "something in the the canine family". -- 70.90.174.173 ( talk) 22:47, 12 February 2012 (UTC) — Preceding unsigned comment added by 70.90.174.173 ( talk) 22:37, 12 February 2012 (UTC)
I don't think Wtshymanski is correct. The s's only cancel out if the later s doesn't have a value > 1. Coulomb has 2 meanings. One is its basic unit value of number of electron charges. Its other use is accumulative. 3 Amps for 10 seconds doesnt equal 3 coulomb. It equals 30 coulomb. And that's the value you would need to use if you use it with joules say to find voltage. That is a large confusion with that stuff, and related to the fact that 1sec is often left off of these formulas. — Preceding unsigned comment added by bobpaul1 ( talk) 00:56, 27 November 2013 (UTC)
https://www.youtube.com/watch?v=Lx64cq0HeXY = MIT course Lec 01: What holds our world together? | 8.02 Electricity and Magnetism, Spring 2002 (Walter Lewin) — Preceding unsigned comment added by 2601:242:4000:6A2:D866:2B7F:117F:B60 ( talk) 18:11, 5 December 2015 (UTC)
https://www.youtube.com/watch?v=Lx64cq0HeXY — Preceding unsigned comment added by 2601:242:4000:6A2:D866:2B7F:117F:B60 ( talk) 18:13, 5 December 2015 (UTC)
The comment(s) below were originally left at Talk:Coulomb/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
There can not be charge smaller than 1.6 E-19 C(electron's charge). And here I see E-24, etc. |
Last edited at 09:34, 27 June 2007 (UTC). Substituted at 12:20, 29 April 2016 (UTC)
In the referenced SI document, we have "la charge élémentaire e est égale à exactement 1,602 17X × 10−19 coulomb", which leads me to wonder (1) where all the other digits come from, and (2) does this imply that there will never be any more refined measurements of ? Can we at least find a better reference for ? Peter Chastain [¡hablá!] 07:03, 12 April 2020 (UTC)
1/1.602176634e-19 ≠ 10e19/1.602176634 98.195.237.62 ( talk) 04:54, 4 July 2022 (UTC)