Talk:Capacitor

Add Voltage Coefficient to Non-Ideal Behavior section

How about adding a paragraph about capacitor value on applied DC voltage in some types of capacitors (especially high-k dielectric ceramics)? This is a common problem which trips up analog designs found with timing circuits, etc. I can get this started from a parameter perspective but do not understand the physics. AnalogGround (talk) 18:38, 18 November 2013 (UTC)

Request for Discussion of {{Semiconductor packages}} in electronic articles

Please see the corresponding discussion thread at Wikipedia talk:WikiProject Electronics. Thanks! • Sbmeirow • Talk • 23:34, 15 December 2013 (UTC)

Semi-protected edit request on 31 March 2014

Reference 26 link is wrong. Please replace: http://www.johansondielectrics.com/technical-notes.html/age with: www.johansondielectrics.com/technical-notes/general/ceramic-capacitor-aging-made-simple.html Thanks. Robiki (talk) 10:23, 31 March 2014 (UTC)

 Done Indrek (talk) 11:54, 31 March 2014 (UTC)

Semi-protected edit request on 27 April 2014

Spelling error. Capacitors are commonly used in electronic devices to maintain power supply while batteries are being changed. Should be: Capacitors are commonly used in electronic devices to maintain power supply while batteries are being charged. Thanks! 69.133.32.134 (talk) 13:07, 27 April 2014 (UTC)

‘changed’ is a correctly spelt word, and I think it makes more sense here. Consider a device that can stay on briefly while its battery is swapped with another. This also applies to non-rechargeable batteries. —James Haigh (talk) 2014-04-27T13:48:29Z

"Replaced" would be more precise and less suspect. After all, charging a battery changes it. Macdust (talk) 20:48, 19 July 2014 (UTC)

Macdust (talk) 00:21, 13 June 2014 (UTC)== please remove hyperlinked reference to "displacement current" ==

The corresponding article shows fundamental disputation and obscurantism and there is no purpose to sending readers there. If you substitute the term "some current" for "displacement current", it is possible for the reader to continue learning about the topic of capacitors without having to escape a rabbit hole first. Macdust (talk) 21:50, 12 June 2014 (UTC)

If you feel there is a problem with the Displacement current article, the best solution would be to bring it up there, rather than unlink all the pages that link to it. I'm not saying you're wrong; I haven't looked at the article yet, I'll do that. --Chetvorno^TALK 22:17, 12 June 2014 (UTC)

Please look at the talk pages when you do. You may agree it is unnecessary to note the problem there. Macdust (talk) 00:21, 13 June 2014 (UTC)

Units

I edited the article to remove nF and mF units because I can't find where they are used in actual capacitors, and mF is a unit that is particularly subject to confusion. I didn't make this stuff up – it's common practice in electronics, consistent with my own (admittedly American) experience. I know I've made this argument before, and listed distributor and manufacturer sites that agree, but can't seem to find it at the moment. I'll note that one of the reverted edits was the caption of an image showing a capacitor marked "10,000 μF". I simply made the caption match the picture. Why shouldn't it? Can someone provide pics of actual physical capacitors that are marked in nF or mF? (pinging @Piguy101 and Indrek) —[AlanM1(talk)]— 21:32, 18 July 2014 (UTC)

Here's a capacitor marked as 22 nF: http://www.ciel-electronique.com/catalogue/Larges/CA122NF500V.jpg

Here's one marked as 4.7 mF: http://img109.imageshack.us/img109/9711/3r8n.jpg

Not that this matters much, because on most capacitors (as with many other electronic components) the value is written in shorthand that doesn't explicitly state the prefix. It's not a very good idea to base Wikipedia style policies on component markings. After all, you wouldn't expect people to write resistances as colour codes, would you?

What confusion exactly is mF subject to? It unambiguously means millifarad. If you're talking about the obsolete "mfd" abbreviation, I don't believe that is a relevant issue anymore; any significance "mfd" has is of a purely historical nature. But if you really believe there is still the possibility for confusion (even though, as I noted on my talk page, at least one instance of mF has been in the article for over a year, possibly a lot longer, without anyone raising concerns over it), how about changing the first occurrence of mF to millifarads (mF) ? Would you find that satisfactory?

Indrek (talk) 22:01, 18 July 2014 (UTC)

@Indrek: I am pretty sure that the capacitor in the second picture is actually 4.7uF, as a 4.7 millifarad capacitor would be much larger than the one next to it. Piguy101 (talk) 23:16, 18 July 2014 (UTC)

I believe that nanofarads is acceptable, but millifarads should not be in the article. This is simply because it is not standard usage (I have no idea why, though). I suppose that changing the first occurrence of mF to millifarads would work. Piguy101 (talk) 23:23, 18 July 2014 (UTC)

Although this may be a bit WP:CIRCULAR, the article on Farad says "The millifarad is not used in practice; a capacitance of 4.7 mF (0.0047 F), for example, is instead written as 4700 µF." Piguy101 (talk) 23:26, 18 July 2014 (UTC)

I am pretty sure that the capacitor in the second picture is actually 4.7uF, as a 4.7 millifarad capacitor would be much larger than the one next to it. I'm not so sure. For one, the capacitor next to it seems to be 47 μF, so it seems reasonable for the yellow one to be in the millifarad range. And secondly, the physical size of a capacitor can't really be used to estimate its capacitance. For instance, I have a 0.1 F (100 mF) cap in my parts drawer that's about the size of an LR44 battery, and dwarfed by some 100 μF capacitors. Other characteristics like working voltage can influence a capacitor's size more than its capacitance.

millifarads should not be in the article. This is simply because it is not standard usage (I have no idea why, though). Well, as I mentioned on my talk page, it's possibly because most capacitors are in the microfarad range and below. Gigaohm resistors are also pretty rare, but that doesn't mean that unit shouldn't be used when appropriate (i.e. when describing a resistor with sufficiently large resistance). I'd still like to hear an actual problem with using millifarads. Indrek (talk) 07:10, 19 July 2014 (UTC)

You're right about the sizes; voltage affects size as much as capacitance. Unfortunately, I cannot see the voltage rating of the blue capacitor in the photo, so I guess that my statement is null. Here is my proposal: nonafarads is fine and the first mention of mF should parenthetically say millifarads. Can we do this? Piguy101 (talk) 12:28, 19 July 2014 (UTC)

Adding to myself: the 10000 uF capacitor in the photo should be labeled as both 10000 uF and 10 mF. Piguy101 (talk) 12:33, 19 July 2014 (UTC)

Both of your suggestions sound good to me. Waiting for @AlanM1's opinion. Indrek (talk) 15:20, 19 July 2014 (UTC)