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{{archivebox|[[Talk:Printed circuit board/Archive1|Archive 1]]}}
==Copper Specifications in the Materials Section==
Can someone who is an expert add in the meaning of terms like 1-oz copper in the specification of PCB conducting layers.
I feel it would be useful to newbies to PCB design to know what is conventional too.
e.g. what is typical thickness for copper on outer layers, inner routing layer, inner plane layers...
What is the relationship between copper layer thickness (in mils) vs a specification like xx oz. copper?
Is it a published spec?
Perhaps some discussion of how the hole-plating process affects the outer copper layer thickness and uniformity...
PLEASE!!!! :-) <small><span class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Ucb-e-shop|Ucb-e-shop]] ([[User talk:Ucb-e-shop|talk]] • [[Special:Contributions/Ucb-e-shop|contribs]]) 19:11, 2 August 2009 (UTC)</span></small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->
==Spam==
Some of the recent paper links are blatant spam


"Lamination

Some PCBs have trace layers inside the PCB and are called multi-layer PCBs. These are formed by bonding together separately etched thin boards."

Also seems like spam [[User:Bengaloorinava|Bengaloorinava]] ([[User talk:Bengaloorinava|talk]]) 07:09, 7 October 2009 (UTC) Bengaloorinava

:Multi-layer pcbs are extremely common nowadays, the article should probably say more. Why do you think this is [[WP:SPAM|spam]]? [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 07:27, 7 October 2009 (UTC)

==Page split suggestion==

Does anyone think we should break this page up into "Circuit boards", "Circuit Board Design", and "Circuit Board Manufacturing" pages? Of course link all three together, so a reader can navigate. These three topics seem like they could be entries on their own, and circuit board seems like it is getting long.

:Your plan sounds fine to me. Perhaps we need another article on prototyping boards, such as stripboard (Veroboard), tagboards, perfboards, wire-wrap, Speedwire. -- [[User:Heron|Heron]] 19:18, 12 May 2004 (UTC)

:OK, I added stuff about prototyping electronic circuits at [[Prototyping]]. --[[User:DavidCary|DavidCary]] 21:01, 28 Dec 2004 (UTC)

==Photo for use in this article==

Please see [[Talk:Microcontroller]] -- maybe the photo in question (shown) could be of use here instead? --[[User:Wernher|Wernher]] 01:51, 24 Oct 2004 (UTC)

== substrate ==

The article once said
"The simplest PCB is a layer of copper foil glued to a sheet of plastic (referred to as the substrate), often an epoxy glue reinforced with fiberglass."

Yes, fiberglass-reinforced epoxy is the most common PWB. But is it technically [[plastic]] ? It's definitely a [[composite material]].

--[[User:DavidCary|DavidCary]] 21:01, 28 Dec 2004 (UTC)

PCBs based on FR4 or other epoxy based materials are sometimes called "plastic" in contrast with circuits on ceramic substrates (what we used to know as "hybrid" circuits).

--[[User:Borborygmus|borborygmus]] 18:32, 2005 Apr 25 (UTC)

Removed reference to "'Pertinax' (a phenol formaldehyde resin), or a fiberglass-reinforced epoxy composite material." This appears to be a bogus entry. Search for this brand name at http://www.thomasnet.com turned up nothing, and in 30 years of working with PCBs I've never heard of the stuff. You'll find this reference all over the Web, usually in conjunction with a discussion of Roman emperor Publius Helvius Pertinax, but it appears to have been gathered from Wikipedia by 'bots.
-- [[User:Hydrargyrum|Quicksilver]] 04:10, 11 Jun 2005 (UTC)

* No, Pertinax is indeed the term used for the resin type board, for instance in Finland. (May be a German trademark?) "Pertinax printed circuit board" gives 294 Google hits. --[[User:Janke|Janke]] | [[User talk: Janke|Talk]] 20:07, 25 August 2005 (UTC)

== Design ==
The statement "Multilayer PCBs have alignment marks and holes " ist not correct, all PCB's need alignment for production. You can design very dens and very fine pitch on 1 and two sided PCB for eg. IC package.
-- [[User:Cello|Cello]] 08:22, 24 Jun 2005 (MET)
:Fixed. --[[User:Heron|Heron]] 08:45, 24 Jun 2005 (UTC)

The statement, "Also, a PCB etches more consistently and tends to resist warpage if all regions have the same average ratio of copper to bare board.", is not entirely true. The advent of spray etching equipment in circuit board job shops has resulted in consistent etching regardless of metal-to-nonmetal ratios. [[User:Hydrargyrum|Quicksilver]] 00:32, 14 October 2005 (UTC)


== Arcade related PCBs ==
There seems to be allot of people intrested in the JAMMA connected PCBs, the Arcade Video Games related PCBs.

== Conductive Inks used on PCBs ==

I believe that conductive inks were in fact used on early PCBs. Hence the term '''P'''rinted '''C'''ircuit '''B'''oard. I'm sure it used to say something about the man who did this in this very article. Will try to find refs before reinserting. [[User:Light current|Light current]] 21:15, 24 August 2005 (UTC)
* Yes please, refs are always nice. "Printed", IMHO, refers to the [[silk screen]] printing used to make the etch resistant mask. --[[User:Janke|Janke]] | [[User talk: Janke|Talk]] 20:03, 25 August 2005 (UTC)
I think you are right about 'printed' refering to a silk screen but I havent found any proof of it yet. There is no mention of how '''Eisler''' first did it in the article [http://en.wikipedia.org/wiki/Paul_Eisler] on him. [[User:Light current|Light current]] 22:26, 25 August 2005 (UTC)

::I'd be surprised to find that PCBs have ever used a much different process than either the good-old subtractive process (print the resist on the copper, etch away the rest) or the (semi-)additive process (which usually involves plating extra copper and then tin/lead into the unmasked areas, followed by a brief etch that removes the original copper from the unplated areas), but there was a brief flirtation with actual printed wiring for the purposes of accomplishing ECOs (Engineering Change Orders). '''The Wired Ink''' corporation were the big proponents of this ca 1978 or so, but I don't think they ever quite got all the bugs worked out of their technology; the company I worked for at the time investigated using this process but ultimately rejected it.

::[[User:Atlant|Atlant]] 23:53, 23 May 2006 (UTC)

Yeah but Im talking EARLY (very early-- before we were born!) pcbs! 8-)--[[User:Light current|Light current]] 00:04, 24 May 2006 (UTC)

::Another pair of topics, though, where Wiki has no coverage (at least according to Google earlier today) are thick- and thin-film circuitry. There, the conductive patterns definitely '''are''' screened directly onto the (usually-ceramic) substrates.

::[[User:Atlant|Atlant]] 00:09, 24 May 2006 (UTC)

Yes thats correct. I think thats how the very first [[Printed circuit board|PCB]]s were made by [[Eisler]] but I cant find the refs! 8-(--[[User:Light current|Light current]] 00:13, 24 May 2006 (UTC)

::Nowadays, Google reveals [http://www.conductivecircuits.com/ Conductive Circuits, Inc.] using the printing-for-rework process.

::[[User:Atlant|Atlant]] 00:18, 24 May 2006 (UTC)

OK. If you were [[Eisler]], what would you have used as a [[conductive]] [[ink]]. (must have been available in the [[fifties]]) 9-)--[[User:Light current|Light current]] 00:22, 24 May 2006 (UTC)

:Photographs (on "paper") are also called "prints", even though they are manufacturered with some opto-chemical process (no "real printing" in the "Gutenberg sense").
:A circuit board can be drawn with a paint which contains silver grains. This stuff is readily available in car supply shops (for repair of the heating traces in the car's rear window). Conductive "paint" is also used for the shielding of electronical devices - for exa,ple, CRTs (TV tubes). Such stuff may be based on graphite, but there also paints which apparently conduct better the graphite-based stuff - at a higher price, but still cheaper than anything with a significant amount of silver in it. Nowadays such stuff can be readily bought in electnics shops, typicaly in the form of spray cans. Such stuff may have been available in the 50s as well.
:And finally, there are paints which are resistant against the etching chemicals. Nowadays, this stuff is typically sold in the form of pens, so a PCB designed can simply draw the traces with such a pen, put the board into the etching chemical (no development needed, as with litographic processes) and finally rub off the paint again (with some "sanding block", for example, to improve the quality of the soldering on the traces). Obviously, similar point can also be used in printing machines.
:Which of these explanations denotes the cause for the naming of PCBs is obviously unknown by me. --[[User:Klaws|Klaws]] 12:41, 5 March 2007 (UTC)

== Cordwood construction don't belong here any more ==

It seems now that 'cordwood construction' does not fit into this article on PCBs as there is no 'printing' involved in it. Any suggestions on where it might be moved to? [[User:Light current|Light current]] 17:22, 30 August 2005 (UTC)

So there you go.. I was wrong again!!--[[User:Light current|Light current]] 18:11, 25 February 2006 (UTC)
:We have an embryonic section in the [[Prototyping]] article called "Electronics prototyping". You could move it there. I think [[Electronics prototyping]] ought to be a separate article, eventually, so that we can include other non-printed and even non-soldered methods. --[[User:Heron|Heron]] 17:34, 30 August 2005 (UTC)
::Yes but its not really a 'prototyping' technique(it was definitely used in missile telemetry and fuzes). Its more of an old fashioned contruction technique. [[User:Light current|Light current]] 17:37, 30 August 2005 (UTC)
:Oh, I didn't realise that. In that case, you could look at [[Electronics]] under "See also" where a few construction methods are listed. Perhaps this list could be separated and expanded. --[[User:Heron|Heron]] 19:02, 30 August 2005 (UTC)

OK Ive added link in ''see also'' in [[Electronics]] but that page is going to need some work. Also [[cordwood]] page needs modifying as it presently only refers to building construction. [[User:Light current|Light current]] 22:01, 30 August 2005 (UTC)

:::Cordwood construction, as described, has ''nothing'' to do with printed circuit board technology, and never belonged in this article from the start. (There ''was'' a version of cordwood that sandwiched components between two PCBs, but I've only read about it, and have never, ever encountered an example, either in industry or prowling through electronics surplus stores.) The section needs to be deleted from this article. It could be set up as a separate Wikipedia historic footnote article. It should ''not'' be included in [[prototyping]], as cordwood was too costly a construction method for that purpose. Early in my career I heard older engineers jokingly calling for prototyping with cordwood, but from the context it was clear that they were ''joking''; nobody ever actually did it in the lab, for obvious reasons. The technique has been obsolete since the late 1960's, pushed aside by integrated circuits. Wherever the article ends up, it should be rewritten in the past tense. [[User:Hydrargyrum|Quicksilver]] 09:06, 4 September 2005 (UTC)

What joins the components together? Is that a PCB (or two) I can see??
[[Image:Cordwoodcircuit.agr.jpg|thumb|800px|One form od cordwood module construction using PCBs.]]
--[[User:Light current|Light current]] 18:08, 25 February 2006 (UTC)

::Cordwood construction '''using PCBs''' was commonly used in the [[Control Data Corporation]] family of computers. One of these days, I'll get the time to shoot a picture of a CDC module that I still have.

::One might also make the argument that a billion Japanese transistor radios used a sort of "half-cordwood" construction. Surely we've all seen 1960s radios that have all the resistors standing vertically with the upper axial lead folded-back to pass down the side of the resistor and re-join the PCB. The resistors even included insulation on the leads to support that packaging method.

::[[User:Atlant|Atlant]] 12:00, 11 May 2006 (UTC)

Yes I ve seen those Japanese radios- very tightly packed. 8-)--[[User:Light current|Light current]] 12:51, 11 May 2006 (UTC)

==Technology Limits==
Should there be something in here about number of layers vs thickness? Concepts of trading off laminate thickness vs characteristic impedance?
What about buried capacitance, this technology does not seem to be mentioned...
Likewise microvias (laser drilling) Should these be added?

== New Section: Important things to consider when engineering a PCB ==

Just some ideas, feel free to work this anyway you want. (atleast a few of these caught my attention, being seemingly absent from the article)

* prototyping
* measurements
* lead spacing
* lead/hole diamaters
* multiple qualifying parts (eg, what if you run out of compenent D1, and need to order a compatible substitute?)
* voltage/current requirements
* track thickness, width, spacing
* noise
* testing/troubleshooting
* supplementry/addon subcicuits
* FCC ID

Embarrasing as it was, I once adjusted the wrong layer (flip side) for a mating contact on the edge of a board. Stupid things like this cost big bucks if you're too rushed for QA.

[[User:66.219.200.235|66.219.200.235]], when you leave comments on the Talk page, please remember to log into Wikipedia with your Username, sign your contributions with <nowiki>~~~~</nowiki>, and ''preview'' your post for glaring formatting and spelling errors before clicking the '''Save page''' button. It would also be helpful to not label new sections "New Section", because in a short while it becomes an ''old'' section. -[[User:Hydrargyrum|Quicksilver]] 18:51, 11 November 2005 (UTC)

== External links ==
This article is in danger of becoming a [[link farm]], contrary to [[WP:NOT#Wikipedia_is_not_a_mirror_or_a_repository_of_links.2C_images.2C_or_media_files|Wikipedia policy]]. -[[User:Hydrargyrum|Quicksilver]]<sup>[[User_talk:Hydrargyrum|T]] [[Special:Emailuser/Hydrargyrum|@]]</sup> 21:58, 6 January 2006 (UTC)

There's a list of CAD packages near the bottom, but no mention of anything by Cadence, including the OrCAD package (which has been around for years) and Allegro. I think it should be added to the list of PCB layout programs but I don't want to add to the link farm problem, so I'm mentioning it here.

Allegro is added, but it points to the wrong place! --[[User:24.46.164.83|24.46.164.83]] 02:35, 3 March 2007 (UTC)

==EDA==
The EDA information is very good. In my organization we are generally working with high frequencies, so that we do all of our component placement and routing by hand; and I'm not real familiar with what's possible in automated placement. But, the description of placing all the components on a rectangular grid seems specific to certain types of design, like large scale 7400-series logic designs. In a design with irregularly sized parts, like a single 50 mm square FPGA surrounded by a mess of 0402 capacitors and a few power supply components, for example, placing the passives on the same grid as the FPGA doesn't seem sensible. Is there a way to describe the auto-placement and routing process that isn't specific to certain types of design? -- [[User:The Photon|The Photon]] 06:30, 10 February 2006 (UTC)

== Link farm ==
Gotta watch this page does not become a link farm!--[[User:Light current|Light current]] 22:04, 18 March 2006 (UTC)


== [[Multiwire]] boards ==
This technique of interconnection with machine routed insulated wires embedded in a non conducting matrix was used during the 1970' to 1980s. Should this be mentioned here or on its own page? --[[User:Light current|Light current]] 01:59, 20 March 2006 (UTC)

:It should at least be referenced here and, I'd argue, included here.

:[[User:Atlant|Atlant]] 23:58, 23 May 2006 (UTC)

Included it. But now the name of the page will need to be changed from PCB to [[Circuit board]] possibly. 8-|--[[User:Light current|Light current]] 17:22, 1 June 2006 (UTC)

== Featured article ==
I feel this is now getting near to the quality of a featured article. Any comments for/against?--[[User:Light current|Light current]] 03:40, 21 March 2006 (UTC)

:Never hurts to put it up for [[Wikipedia:Peer review|Peer review]], at least. -- [[User:The Photon|The Photon]] 05:50, 21 March 2006 (UTC)

After reading this article I thought it should be featured ... in fact I came here (the discussion) to suggest it as a featured article. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/92.2.30.182|92.2.30.182]] ([[User talk:92.2.30.182|talk]]) 06:19, 22 April 2008 (UTC)</small><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Hey some help in writing a paper? ==

Hey, i was just wondering what kind of information would sound good in a report about the History of comps. So far i have used a lot of encyclapedias (actualy book) but it seemed to me like they all said the same exact thing. Could any one help plaese? Im running out of information on this main page!

sorry person above is Glitch481

== Etching- where is it? ==

Have I missed it, or is there actually nothing on this page on the important subject of actually ETCHING the board? THis omission needs to be remedied quickly!--[[User:Light current|Light current]] 04:08, 30 May 2006 (UTC)

:It was there, but now it's more obvious.

:[[User:Atlant|Atlant]] 13:47, 30 May 2006 (UTC)

Yeah Ok. But I think we need quite a bit more detail on the (chemical) etching process.
*different sorts of etchants (FeCl3, ammonium persulphide, copper sulfate, etc)
*track undercutting,
*definition,
*problems etc etc.

Could turn into a page all of its own after being nurtureed and fed here! --[[User:Light current|Light current]] 17:04, 30 May 2006 (UTC)

== Populated pcbs ==
Moved here from page beacuse testing of populated pcbs is not really about pcbs, its about completed electronics assembly testing ATE etc

''After the board is populated, the interconnection between the traces and the ICs may be tested by [[boundary scan]] techniques. In boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the pcb traces to test that the ICs are mounted correctly. Boundary scan testing requires all the ICs to be tested to use a standard test configuration procedure, and the most common one is the Joint Test Action Group ([[JTAG]]) standard.''

--[[User:Light current|Light current]] 17:13, 30 May 2006 (UTC)

:Yes, you are right. But by the same argument, the entire section on populating and conformal coating are not relevant to this article. Furthermore, the disambiguation page [[PCA]] has a link here. Also, very few people in common talk make a distinction between a PCB and a PCA. A general encyclopedia reader, seeing a PCA in their VCR or TV set and trying to find out how its made is more likely to look it up as a PCB than as a PCA. Rather than try to fork off a new article for [[Printed circuit assembly]], I've added a bit of verbiage to the lead section to expand the scope of this article to include PCAs as well. I've also rearranged the test and populating sections to reflect the distinction between PCA and PCB -- the PCB test is done before populating. Finally I put the JTAG material back in, but into the section on populating, again to clarify the distinction between a PCA and a PCB. Seem reasonable? -- [[User:The Photon|The Photon]] 04:57, 31 May 2006 (UTC)

Well wouldnt it be better to rename this article [[Printed circuit assembly]] or [[Circuit board]] which is a more common name, with redirect from [[Printed Circuit Board]]? 8-|--[[User:Light current|Light current]] 15:02, 31 May 2006 (UTC)

:At the moment, [[Circuit board]] redirects here. Problem is, that's not really correct since wire-wrap and other types of circuit construction probably also would be considered ''circuit boards''. -- [[User:The Photon|The Photon]] 04:26, 1 June 2006 (UTC)

== Steel substrates ==
On disassembling a defunct 3.25 FDD recently, I was surprised to find that the PCB substrate appeared to be steel. I dont know the reason for this and its the only one Ive ever seen. Anyone have any more info on steel substrates and their advantages? 8-?--[[User:Light current|Light current]] 16:39, 31 May 2006 (UTC)

: Some metallic substrate exist ([[Power electronic substrate]]), but as far as I know, they are mainly made of aluminium, and sometimes copper. I can't remember having seen any of those made of steel. Maybe it is for EMI shielding purposes? - [[User:CyrilB|CyrilB]] 17:05, 31 May 2006 (UTC)

Yeah but this was definitely steel- I tested it with a magnet. Only reason I can see for them using it is that its cheaper than copper or aluminium 8-?--[[User:Light current|Light current]] 17:37, 31 May 2006 (UTC)

:In the case of a HDD, it might be used to protect the disc from magnetic fields. Is the substrate part of the motor? This kind of setup is sometimes used in VCRs. - [[User:CyrilB|CyrilB]] 19:11, 31 May 2006 (UTC)

::Could it have been structural? In small disk drives, there's a very definite contention between the total available thickness and the thickness consumed by the platter stack-up; making the PCB a stressed member might mean that there's no need for some separate structural member so they can fit a millimeter or two worth of platters in there. Remember, disk drive frames have to be quite rigid to absorb the forces of the head-positioning mechansisms yet keep the heads on track.

::[[User:Atlant|Atlant]] 00:48, 1 June 2006 (UTC)

Well I think it '''may''' have been structural altho' it did not seem to be part of the platter assy. But I cant tell now as I think I have thrown it away as being useless (silly me). Ive got so much junk you wouldn't believe it (OK maybe you would) 8-)--[[User:Light current|Light current]] 00:56, 1 June 2006 (UTC)

::I'd believe it! ;-)

::[[User:Atlant|Atlant]] 01:01, 1 June 2006 (UTC)

Yeah. Anything that goes wrong I take apart and, if I cant fix it (which is usually the case), I completely dismantle it and say to myself of a component or assy (or bit of metal even): ''that looks interesting -- I may be able to use that in the future''. So I keep it - sometimes for years (and years). Does this sound familiar to anyone?
--[[User:Light current|Light current]] 01:13, 1 June 2006 (UTC)

== Merge tag ==

The merge should not be carried out for the article [[PCB layout guidelines]] should be transwikied to Wikibooks since it is a how-to like manual. [[User:Lincher|Lincher]] 02:20, 17 September 2006 (UTC)

== Too many external links ==

The number of external links on this page is far more than even a liberal reading of [[Wikipedia:External links]] would suggest is healthy. Right now, it seems to be serving as a links directory for software, design documents, magazines, and more. There are 35 (!) links in the section right now. Ideally, it would be no more than five, though I can't see pruning this list to so few, realistically. Particularly, the software and magazines should go—the software because it's already internally linked (them that are notable enough to have articles) above in the ''see also'' section, and the magazines because [[WP:NOT|we're not a links directory]] (if any have article, a ''see also'' link would be apropriate). If there are no major objections after a while, I'm going to clean the external links section out. &mdash; [[User:Saxifrage|Saxifrage]] [[User talk:Saxifrage|✎]] 04:42, 4 October 2006 (UTC)

I don't think that advertising is the point of wikipedia so I'am removing this [[Wikipedia:Vandalism]]. removing a link from External links.--[[User:Kid42day|Kid42day]] ([[User talk:Kid42day|talk]]) 07:40, 2 January 2008 (UTC)
:Just to be clear: you're not removing it as [[Wikipedia:Vandalism]], you're removing it as [[Wikipedia:Spam]]. There's an important difference. —[[User:Angr|'''An''']][[User talk:Angr|''gr'']] <sup>[[User:Angr/If|If you've written a quality article...]]</sup> 08:04, 2 January 2008 (UTC)

I notice that the links to sites that show how to make a PCB yourself were retained. Is there any reason why a page can't be started here on wikipedia to document some of that information here rather than linking out to other sites? Obviously, I'm not suggesting that the content of those sites be stolen, but if I wanted to document some basic methods that I have learned on my own here on a new page, is there a reason to not do that? <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/66.13.172.19|66.13.172.19]] ([[User talk:66.13.172.19|talk]]) 21:08, 1 June 2009 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Introduction ==

Could the inroduction please put pcb's in better context with a sentance such as "PCB's form the basis of most electronic devices from TV remotes to personal computers". The introuction is too technical and offers no clue as to how widespread pcb's are. <small>—The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by [[Special:Contributions/68.226.90.205|68.226.90.205]] ([[User talk:68.226.90.205|talk]]) 03:14, 6 April 2007 (UTC).</small><!-- HagermanBot Auto-Unsigned -->

== Bare board vs. assembly ==

It seems as though we have intermixed bare board info with assembly-related sections in this article. How about separating these and rearranging the sections so that we cover both, but do it in an organized fashion? [[User:Leon7|Leon7]] 19:52, 11 May 2007 (UTC)

==Sick or silk==
"Sick" screen printing is mentioned in the Manufacturing Section. Is that a typo? <small>—The preceding [[Wikipedia:Signatures|unsigned]] comment was added by [[User:76.17.107.204|76.17.107.204]] ([[User talk:76.17.107.204|talk]] • [[Special:Contributions/76.17.107.204|contribs]]){{#if:{{{2|}}}|&#32;{{{2}}}|}}.</small><!-- Template:Unsigned -->

:Almost certainly; I'll fix it.

:[[User:Atlant|Atlant]] 20:45, 29 May 2007 (UTC)

::It was just vandalism by {{IPvandal|84.12.54.53}}.

::[[User:Atlant|Atlant]] 20:46, 29 May 2007 (UTC)

== Alternatives ==

Can someone add a list of alternatives to the Printed Circuit Board. I'm doing an assignment due first week back on the third term, yes I'm from Australia, and I need to find some alternatives to the Printed Circuit Board. All I need is a list and I can find out the rest myself. &#9786;[[User:Efansay|<span style="color:#000066;font-weight:bold">E</span>fansay]]<sup>[[User talk:Efansay|<font color="Purple">T</font>]]</sup>/<sub>[[Special:Contributions/Efansay|<span style="color:Goldenrod">'''C'''</span>]]</sub>&#9786; 05:37, 3 July 2007 (UTC). P.S. I am a student from a selective high school. See my user page by clicking on [[User:Efansay|this link]] to find out what school that is.

== suggestions from plating shop QA guy ==

1. when I was a kid there were some tube TV circuit boards, single sided like the cordwood things, that the local TV repair guy said were phenol-formaldehyde. The boards broke/looked like P-F filled paper. Did not seam stable to soldering repair temps.

2. The conductor we know is OFC (oxygen free copper), low ohms/(cm squared). Conductive inks, ranging from powdered carbon, colloidal carbon, copper powder, silver powder. Volatile solvent with viscosity/cement (make sure doesn't wet surfaces) so conductive particles touch on edges. Even tight packed ~5% particle to particle contact. C.F. Powder Metallurgy. Early 60's 100's of ohms today 10's of ohms per inch but best silver ink uses solder temps to cure. Don't know any low ohm conductive plastic. Re "silk screening conductive ink": practical limit is cost. Resist mask is low viscosity. Solder paste, like conductive ink, is metal powder in carrier of constrained viscosity. Delivering little dots of solder paste to individual tiny lands is a reliability limiting step, think cost. Delivering enough thick conductive ink to many square inches worth of traces reliably would certainly affect the cost. Any idea of the thickness of conductive ink to supply tube heater circuits let alone a CPU (say 40 Amps @ 1.2 volts?)?

Yes, I have used "silver pens" to repair circuits. Cool. Tried to draw circuits. Real pain after first dozen lines. Transistors OK but trying to glue ICs using the silver ink, ugh. Didn't solder as well as stated.

3. in the 90s "unnamed Japanese company" was using full build electroless copper for their PCBs. Electroless copper (alkaline copper edta formaldehyde) has high oxygen and high ohms per square cm but probably OK for CMOS. Unsure of their power planes.

4. Questions about impedance etc: one place I was at had 16 layer mixed signal boards ( I failed a few lots on examining sections) that used several layers of (ground and) power planes to isolate signals. More layers seem to lead to higher rate of failure. Another company limited to 8 layers max(!). On one of their popular products, a redesign of a custom ASICs pinout (they had a silicon fab for prototyping) allowed going from 4 layer to 2 layer board and improved overall yield.

5. "average area of copper"?? Never heard about warpage issues due to etching. However surface conductors and vias (holes)(rem only a few mils of electroless copper) were built up in acid copper baths. The acid copper was operated to get pretty good throwing power for the holes but could overplate surface features (instead of a mesa shape cross section of the copper trace it would look like a mushroom) if extra copper area was not there. Also consider that the ground and power planes are usually the outside layers (rem we add copper which improves current carrying capacity) and helps improve radiation and crosstalk of inner signal lines.

6. Some engineers are wary of using silver due to silver whisker and related issues. Bright tin most prone to tin whisker, stress in tin crystals seem to push out whiskers. Solder and matte tin plating have less whisker problems. Solder plated boards more likely to be reflowed after etching, which relieves stress. Lead solder exhibits tin whisker also, when solder solidifies the tin and lead crystals are separate. Tin pest deteriorates storage of boards at cold temps.

7. On steel. Surface mount RF components on conductor (traces as waveguides) been around for awhile. With blind vias ending inside multilayer board the conductive layer (steel can be passivated to be non-conductive surface) could be stiffener. The temperature range of epoxy-fiberglass boards is limited to that of components on the board (or the ICs fail off). Assume that coefficient of thermal expansion of the steel plate is compatible?

8. between bed-of-nails and jtag might want to mention machine vision. Several video card makers invested significantly in machine vision for PCB testing vs human eye. (machine vision picks out bad potato chips on a fast conveyor belt, too).

9. To get the holes drilled in a finite time the drills run a thousands of RPM, hit temperatures of several hundred degrees. The drills tipped with WC (hardness 9.5?), softens/ oxidizes with heat, going thru glass fiber ~7.5 hardness. Some of the epoxy chemical of the board breaks down (smears) due to heat and oxidation. After drilling the boards they go into 98% sulfuric acid or KOH/glycol to swell/remove some oxidized plastic. Next is usually alkaline permanganate, further etches back plastic, allowing exposure of inner layer copper traces. The Manganese DiOxide from the reaction is a tough coating adhering to exposed plastic of the board (the hole) and copper. Next is usually to etch back glass fibers with Ammonium Fluoride. Next steps vary. In one method a sulphide bath converts MnO2 to Manganese Sulfide, the semiconductive MnS catalyzes electroless copper deposition from alkaline copper edta formaldehyde system. Other two methods use a reducing bath to remove the MnO2 then adsorb either colloidal carbon or Palladium - Stannous TriChloride complex to deposit a conductive coating to the thru hole, then electrolessly copper plated. Copper Sulfate Sulfuric acid bath quickly plates high conductivity copper. Nickel Chloride strike then Nickel Sulphate bath (softer plate, small pores). Then hard gold from acid gold cyanide with citric acid sacrificed (oxidized) at (inert non-gold)anode (few ppm nickel or cobalt to harden gold).


[[User:Shjacks45|Shjacks45]] 11:53, 28 September 2007 (UTC)

== Colouring? ==

Are there specific reasons why the PCB's in the older generations (before they come up with other colours in ~1995-2000) are either light brown or green?

[[User:K61824|K61824]] ([[User talk:K61824|talk]]) 02:23, 16 December 2007 (UTC)
:For non soldermasked boards the color is usually the natural color of the base material (though there are exceptions), this is a deep brown for SRBP and a light beige for fiberglass. Soldermasked boards are traditionally green, I belive green was chosen because using a color our eyes are more sensitive to makes inspection easier. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Plugwash|Plugwash]] ([[User talk:Plugwash|talk]] • [[Special:Contributions/Plugwash|contribs]]) 12:44, 17 December 2007 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

== PCB router ==

What is a PCB router ?. --[[User:Nopetro|Nopetro]] ([[User talk:Nopetro|talk]]) 11:06, 18 February 2008 (UTC)

There are two very different things called a "PCB router":
* [[router (woodworking)]]: a motorized tool that holds a cutting router bit used to cut the PCB out of a large panel. Most PCBs are simple rectangles, but when a PCB has a complex concave shape, or has internal cutouts, the radius of that router bit gives the minimum [[fillet (mechanics)|fillet]] radius of the concave corners. This "route" is the cutting path.
* [[routing (electronic design automation)]]: software used to lay out the traces on a PCB or IC. Most modern PCB design software includes both an autorouter and manual routing tools. This "route" is the path of the conductive traces.
--[[Special:Contributions/68.0.124.33|68.0.124.33]] ([[User talk:68.0.124.33|talk]]) 15:24, 24 November 2009 (UTC)

== Making one? Design Services? ==

Hi, I'm a mechanical engineer and have very little to no knowledge about this technology. However I am in the process of making a product that will need a circuit board for it's controls. I have aboslutely no idea of these things are made or how to make them. I have been wondering if there is perhaps a company that can design these for you? for a reasonable price, of course. Please let me know if any of you have any information that can be of any help. ([[User:Alkaroth|Alkaroth]] ([[User talk:Alkaroth|talk]]) 13:47, 13 March 2008 (UTC))

:Since Wikipedia is not a forum or message board, you are kindof coming to the wrong place. I wish you the best of luck, but you are not going to get the info you need here. Really, though, good luck! --[[User:Jaysweet|Jaysweet]] ([[User talk:Jaysweet|talk]]) 13:50, 13 March 2008 (UTC)

== Other Acronyms ==

I think I've seen some other alternative acronyms for these type of boards, but I don't know what they really mean. The two I've seen are PWA and ECA, which I believe to be Printed Wiring Assembly and Electronic Circuit Assembly, respectively. Would some kind soul please verify and integrate these? [[Special:Contributions/192.91.173.42|192.91.173.42]] ([[User talk:192.91.173.42|talk]]) 13:53, 29 April 2008 (UTC)
* It should be noted that these terms both imply at least one distinction: between the laminated insulator & conductor PCB, and the multi-piece object that consists of a PCB/PWB plus the soldered-in electronic devices, sockets, heat sinks, etc. (and, if the PWB is designed for sockets rather than soldered-in ICs, possibly the plugged in chips). <br>--[[User:Jerzy|Jerzy]]•[[User talk:Jerzy|t]] 05:03, 19 October 2009 (UTC)<br>

::Yes, that's right, PCB strictly speaking, refers to just the board with the printed wiring. PWA and ECA refer to the completed assembly with all the components in place. Plus ECA does nto necessarily imply a PCB is being used. Although PCBs are ubiquitous in modern electronics, many other manufacturing methods were used in the past (and still are in specialist applications and prototyping). [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 18:25, 19 October 2009 (UTC)

::: What are CCAs? The [[Aviation Electronics Technician (United States Navy rating)|Aviation Electronics Technician]] article briefly mentions in passing "circuit card assemblies (CCAs)". Is CCA yet another synonym for PWA, or is it a more general term covering any circuit "manufacturing method" you mentioned?
::: Is there a general article about all the [[electronics manufacturing]] and [[prototype#Electronics_prototyping | electronics prototyping]] methods? Methods such as [[stripboard]], "Manhattan style" aka "Insulating Pads Soldered to a Ground Plane", [[point-to-point construction]], [[wire wrap]], etc. --[[Special:Contributions/68.0.124.33|68.0.124.33]] ([[User talk:68.0.124.33|talk]]) 16:07, 24 November 2009 (UTC)
::::If you have done any work at all for the military, you will know they have acronyms coming out their ears. This is probably just another such non-notable piece of jargon. Sounds like a good article for you to write, don't forget all the miniaturized and high frequency techniques such as, [[hybrid integrated circuit]], [[thick film technology]], [[stripline]] and [[microstrip]]. [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 18:39, 24 November 2009 (UTC)
::::: I guess I'll start adding various manufacturing methods to the end of the [[electronics manufacturing]] article, until someone figures out a good name for that more general article. --[[Special:Contributions/68.0.124.33|68.0.124.33]] ([[User talk:68.0.124.33|talk]]) 06:04, 10 December 2009 (UTC)
re:"What are CCAs?" defined on one page <ref>http://www.tpub.com/content/logistics/59/98/666/01-202-5397.htm</ref> as "A grouping of two or more physically connected or related" parts. "The item is generally part of a subassembly and cannot be assigned a more definite item name...Excludes PRINTED CIRCUIT BO" Slightly related, I've seen PWB/PWBA/PWA used in commerce more frequently than the PCBA acronym. My comment specific to the USA. <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/71.134.158.42|71.134.158.42]] ([[User talk:71.134.158.42|talk]]) 19:03, 26 December 2009 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Invisible inventor ==

Why has the inventor ([[Paul Eisler]]) of the PCB been excised from this article?--[[User:ProperFraction|ProperFraction]] ([[User talk:ProperFraction|talk]]) 01:50, 27 June 2008 (UTC)

== Nothing on PCB Design? ==

There's nothing on actually designing a PCB here. I believe a small section on design of PCBs should be added, including stuff like auto-routing algorithms, manual routes, etc. <small>—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Zohair.ahmad|Zohair.ahmad]] ([[User talk:Zohair.ahmad|talk]] • [[Special:Contributions/Zohair.ahmad|contribs]]) 05:19, 3 August 2008 (UTC)</small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

== Arcade PCBs/Game board ==

Arcade boards should be classfied as PCB. <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/125.160.195.242|125.160.195.242]] ([[User talk:125.160.195.242|talk]]) 23:54, 14 October 2008 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Merge from Signal trace ==

[[Signal trace]] is a three-sentence article. I think it should be part of this article. Does anyone object? --[[User:Hughcharlesparker|Hugh<small>Charles</small>Parker]] <small>([[User talk:Hughcharlesparker|talk]] - [[Special:Contributions/Hughcharlesparker|contribs]])</small> 13:10, 23 October 2008 (UTC)

:I agree it should be merged/incorporated. I also have some beef with the term itself. In my experience (30 years) the conductors on a PCB were always called ''''tracks'''' (I'm Aussie). And not all 'traces' on a PCB are for signals. Many are for power.<BR>
:'''--[[Special:Contributions/220.101.28.25|220.101.28.25]] ([[User talk:220.101.28.25|talk]]) 04:26, 1 November 2009 (UTC)'''

::The term "trace" is very widely used among designers and their automated tools. [http://books.google.co.uk/books?q=pcb+trace&btnG=Search+Books Google books] quickly confirmed my own experience. I think possibly there is a split between designers and production/service terminology here, but you should also be cautious over assuming your own regional terminology is the case elsewhere - for instance, while in Australia I was surprised to learn that you don't have light bulbs, but use globes instead. On the question of there also being power traces, the article does mention this point, using up one of its precious three sentences to explain this, and again, Google books confirms that [http://books.google.co.uk/books?q=pcb+signal+trace&btnG=Search+Books signal trace] is accepted terminology. [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 11:00, 1 November 2009 (UTC)

:Now, now Spinningspark, I wasn't assuming everyone used the same terms. Remember Australia is a 'multi-cultural' society. I've been Googling things myself, but that would surely have to have a bias to American/US terminology (& spelling!) as US is where the Internet and a great deal of HiTech has originated and is written/web hosted too?. ie Printed Circuit Boards first developed in USA? And there's 15 of you for every one of 'us'! Makes a difference too.<br>
:I understood what was being said and that's the main thing. Possibly we are more aware of US terminology than US editors are of 'ours'? I have also put 'track' in the article intro (what 'youse' guys seem to call the 'lede') as an alternative term! ''Trace'' may come from the fact that nice wide 'tracks' are now so ''thin'' that they are indeed mere 'traces'! (Just a guess) We↓ also tend to call anything that's longish, thin, flattish and used to go from A to B a 'track' ie 'bush track' (what you might call a forest 'trail' or 'path'?)<br>
:Light bulb/globe? I think the terms are basically interchangeable here. I know I use both. I think we tend to call the 'fluoro'(energy saving) type lights bulb/globe as well, and many of them aren't ''round'' at all. Finally I havent been around PCB design much, and engineering types and production/service people do tend to move in different circles. Found most engineers a bit odd, but then majority were in management, not technical positions!
'''--[[Special:Contributions/220.101.28.25|220.101.28.25]] ([[User talk:220.101.28.25|talk]]) 18:44, 19 December 2009 (UTC)'''

== Immersion Gold ==


'''== Immersion Gold =='''


* Immersion Gold Coating for [[PCB]]

* Lead free soldering

* Protection in environments

* The gold thickness is 1u"-3u",special requirement will be thicker than this thickness.

* Dummy plating free electroless nickel

* High volume production for [[Printed Circuit Board]]

* Durable use for electronic products.

* One of the best Surface Finishing of [[Printed Circuit Board]]




----


'''== Other Calling =='''

* [[ENIG]] - Electroless Nickle Immersion Gold




--[[Special:Contributions/218.13.189.93|218.13.189.93]] ([[User talk:218.13.189.93|talk]]) 11:14, 15 January 2009 (UTC)

== DIY links ==

There were DIY PCB links at the bottom of this article a few days ago. I found them quite interesting and maybe I'll even try those methods some day. They were obviously removed by 210.89.49.199 without explanation. I guess the delete should be undone and the links kept. <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/78.90.39.104|78.90.39.104]] ([[User talk:78.90.39.104|talk]]) 16:26, 6 April 2009 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

==Synthetic biology==
According to [[Angela Belcher]] of the MIT, PCB's can be made using biological organisms. Please include in article. <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/81.245.181.52|81.245.181.52]] ([[User talk:81.245.181.52|talk]]) 07:33, 13 April 2009 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

==CAD==
could CAD files possible also be used to replace extended gerber files ?
that way, cad models (which are already used widely) could be used to inmediatelly tell machines on how to make them <span style="font-size: smaller;" class="autosigned">—Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/91.176.1.77|91.176.1.77]] ([[User talk:91.176.1.77|talk]]) 17:15, 4 July 2009 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Recycling ==

A recently deleted edit read: ''Recycling - This stub needs to be expanded'', which was reverted on the grounds the article is not a stub. I think perhaps the IP editor was trying to say this article should describe recycling of pcbs. I agree with the IP, this has been the subject of recent legislation. [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 17:00, 11 August 2009 (UTC)

== from PCB shop chemist ==

: ''The following content has been copied from [[Talk:PCB]], where it had no point. The heading was given it by the colleague who signed it.''<small> --[[User:Jerzy|Jerzy]]•[[User talk:Jerzy|t]] 21:00, 15 October 2009 (UTC)</small> <br>
PCB printed circuit board<br>
Mostly I've worked at shops making copper clad glass epoxy boards, 2 to 14 layer. Long and sensitive process from drilling holes, desmear, thru hole electroless copper, resist plating (solder or gold), etching. Some special boards: teflon, silver.<br>[[User:Shjacks45|Shjacks45]] 06:43, 28 September 2007 (UTC)
* I just undid the fresh removal of the section ''from this'' talk page. Contributors working in what is justly called the real world actually know a lot that students and academics may not. Let it stay until the page is due for archiving. It lists specific processes & techniques that may be worth including, if they can be documented, or suggest others to someone. If you think that's impossible, say why here, rather than creating a disparity between content, archive, and edit history that can potentially help obstruct detection of vandalistic talk deletions. If it's clutterish, it can be struck thru to speed the process of skipping past it, if there's a consensus for that fact. <br>--[[User:Jerzy|Jerzy]]•[[User talk:Jerzy|t]] 01:47, 16 October 2009 (UTC)<br>
::What are you talking about, those aren't suggestions for article additions (all in there anyway), it is the guys resumé. You're the one making a mess of the history by cut and pasting from the page it was posted on to another page. I work in the real world as well by the way, in this industry as it happens. [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 02:05, 16 October 2009 (UTC)
::* Perhaps i've been [[WP:AGF|AGF]]'g here in the fake world too long: i was unsure whether to construe it as conversation, a request that topics be covered, or an offer to write on those topics; any form of solicitation of paid work never occurred to me. On the other hand, reviewing it in light of your confident assertion, i looked at that colleague's contribs, and discovered contrary evidence:
::# They continue to edit talk pages here occasionally, including 2 months ago, rather than just having made a brief stop to drop a solicitation here.
::# In [http://en.wikipedia.org/w/index.php?title=Plating&diff=prev&oldid=164635358 their only article edit], they added the sentences
::#:: When plating on Iron or Steel, an underlying plating of Copper allows the Nickel to adhere. The pores (tiny holes) in the Nickel and Chromium layers also promote corrosion resistance."
::#: and
::#:: A high current is used, in part to stabilize a thin layer of chromium(+2) at the surface of the plated work. Acid Chrome has poor throwing power, fine details or holes are further away and recieve less current resulting in poor plating.
::#: They also reworded several phrases. (With the exception of downcasing of the names of chemical elements and fixing of a spelling error, the edit has FWIW stood the test of time over the succeeding 24 months.)
::# Another edit they made, on this very talk page, was the addition 5 hours later of [[Talk:Printed circuit board#suggestions from plating shop QA guy]]; its content is clearly intended as article-content suggestions, and IMO the explicates the resume-like tone of the previous talk edit we are discussing as a claim of expertise (in which case it can be on-topic on a talk page, despite the resemblance to a resume).
::: Editors may not simply remove good-faith discussion, which this section must be assumed to have been, at ''least'' from the point when i appended my comments to it. (There is not a consensus, last i checked, that even [[WP:NPA|PAs]] can be removed. Where discussion pages are concerned, both clutter & PAs are better handled with strikethru, as also -- for the sake of effectiveness of talk page audits -- vandalism that is that not removed before the next edit to the page, even if it would be a clearcut [[WP:G3|G3 CSE]] if it were the content of a new article page.)<br><!--
--> For the record, i regard the removal as reckless (independent of the actual evidence i've now cited of good faith in the [[Talk:PCB]] edit), by reason of inferring intent from such casual and confusing Talk:PCB wording, by reason of ignoring a colleague's explicit requests
:::: If you think that's impossible, say why here, rather than creating a disparity between content, archive, and edit history that can potentially help obstruct detection of vandalistic talk deletions. If it's clutterish, it can be struck thru to speed the process of skipping past it, if there's a consensus for that fact.
::: and by reason of having done the removal, either without knowledge of whether the topics are now "all in there", or (apparently) without caring whether the Talk:PCB discussion ''preceded'' their inclusion and thus may be part of the history leading to their inclusion.<br> --[[User:Jerzy|Jerzy]]•[[User talk:Jerzy|t]] 04:53, 19 October 2009 (UTC)<br>

== Breakout board ==

''[[Breakout board]]'' redirects to this article. What is this? --[[User:Abdull|Abdull]] ([[User talk:Abdull|talk]]) 16:24, 10 December 2009 (UTC)

:It is a board that gives access to individual pins of a connector ([http://www.rhonmac-cnc.co.uk/Breakout_board_3.jpg example]) or a chip ([http://onlinetps.com/shop/images/Items_Images/ATMEGA128_Breakout_board.jpg example]). Usually used for prototyping or test purposes, but can be used in small scale production runs when the cost of developing a surface mount board would be too high for the numbers being made. [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 17:13, 10 December 2009 (UTC)

== Glossary ==

I have undone [http://en.wikipedia.org/w/index.php?title=Printed_circuit_board&diff=next&oldid=331661408 this edit]. I did not much care for the misleading edit summary which hides the fact there was a different link there before and this one has replaced it, if there is an argument for one site being better than another, the argument should be made first. I don't think, in any case, there is a real need to link to the glossary of terms on any site. In general these are linked merely as an excuse to get a link on to the website of a manufacturer or supplier and that is not what Wikipedia is here for. There is no reason a glossary cannot be created as a Wikipedia article, see [[glossary of rail terminology]] for a good example of how this could be done. [[User:Spinningspark|<font style="background:#FFF090;color:#00C000">'''Sp<font style="background:#FFF0A0;color:#80C000">in<font style="color:#C08000">ni</font></font><font style="color:#C00000">ng</font></font><font style="color:#2820F0">Spark'''</font>]] 12:47, 18 December 2009 (UTC)


== X-ray picture ==
== X-ray picture ==

Revision as of 06:04, 21 May 2010

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X-ray picture

X-ray zoom series on an old token ring network adapter card

I have removed this image from the article. It is a nice picture, but I don't quite see the relevance that it has to the article text (it was inserted into the test section). If it does have relevance, we need some text to go with it to explain. SpinningSpark 12:20, 5 April 2010 (UTC)[reply]

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