Re: 7 seg LED display pin-out


> I am in need of the pin-out for the HDSP-5621 .56" Dual 7 segment LED > High Performance Green display. Right hand decimal point. Common > Anode. >

This isnt' a design question, and you obviously haven't looked very far.

A clue, though I don't know why I bother when you can't post in the right place, is that there is a far level of standardization, so find a pinout of that sort of device (and if you don't know where to look, you shouldn't be posting in .design) and likely it will be a match.

For that matter, by the time you get to the .design stage, you'd not have to ask, you'd have figured out how to get the pinouts using the device at hand.


Can someone put a copy of the datasheet on abse, or send me the > pinout, or advise a URL for the datasheet. > > thanks MikeN
Reply to
Michael Black
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Well - we have been sucking on a lemon this morning - haven't we.

My enquiry evolved when the usenet feeds to NewZealand fell over (blame our telcos) and I was trying to confirm a pinout before continuing with a design I was contemplating.

My usual source wasn't responding, hence my enquiry to the wider world.

It transpires that the device isn't quute as standard as you have suggested. Several pinouts of very similar devices exist.

Where do you suggest I should have looked?


Reply to

Don't mind them, Mike. Some folks really can't follow their own advice: if the posted question bothers them so much, DON'T REPLY. Fer chrissake.

But then, what would they do with their lives if not reply to messages they detest? Ooo, a conundrum...

Reply to
Anon bozo

It's very simple to figure out. Just use a 3V battery and a small resistor. Hook it up to pair of pins and you will see a pattern. If you can't even do that, then forget about doing the design.

Reply to

Well bozo, what we have is a newsgroup full of junk. NOt just the political stuff and the posts about the weather, but idiots like the original poster who thinks the pinout of an LED display is a "design" question. We get people posting here who even say "well this seemed to be the busiest of the sci.electronics.* newsgroups so I'll post here". We get people posting "I know this isn't a design question, but I'll post anyway". People asking about software that doesn't belong here, and all kinds of other junk.

LIke I keep saying, back in 1995, sci.electronics was split into the multiple groups we see today. Back then, some decided the traffic was too much, and breaking it down into more specific newsgroups would ease the matter.

But, idiots like the original poster put it all back together. Don't find the right newsgroup to post in, just add to the clutter of At this rate, we might as well close down all the rest of the subgroups, because they get underused while the posts that belong there land here.

When bozos can't be bothered posting in the right place, I no longer feel particularly interested in going out of may way to help them. Thus instead of getting an answer by posting "where there's lots of traffic" they may just not get a good answer. I should also point out that when beginners foolishly post here, they are more than likely to not get a good answer either, because the "regulars" who think sci.electronics.deisgn is their hangout take the questions litterally, and don't provide an answer that's useful to a beginner.

Not only was this not a design question, but only a beginner would be puzzling over the pinouts. Anyone who is really up to posting in .design (at least as it was originally intended) would either have resources that would help them with the pinout (either directly, or have the background to know where to look), or hey, they'd know how easy it is to trace out the pinouts of an LED display. You get a voltage source, a current limiting resistor, and put that display in a breadboard, and trace away. It won't take very many tries to get a common pin, and then it's real easy to map out the rest.

If the bozo who started this thread had asked where this level of question belongs, sci.electronics.basics then I would have responded to a beginner. If he'd asked in sci.electronics.components I might have simply ignored the question, depending on whether or not I felt like putting effort into providing an answer.

But once he wants to pose as a "designer" then he deserves to be ill-treated when he immediately shows off his lack of knowledge.

Once again, for the clueless, read Mark Zenier's guide to the sci.electronics.* hierarchy,


Reply to
Michael Black

So lament! But why add to the crap by replying to a post you don't think necessary or appropriate? It's akin to replying to a troll...

Reply to
Anon bozo

That's called, variously, trollfeeding or trollbaiting, but in this case, I don't think either you or miken was trolling - Michael is merely flaming.

Welcome to the zoo! ;-)

Cheers! Rich

Reply to
Rich Grise

Hi Michael,

I decided to celebrate catching up with a 6 month backlog of this group (largely by tossing out most of the noise and crap) with a rewrite.

Comments, anyone?

Viewers Guide to the USENET sci.electronics newsgroups. [March 24, 2007]

This FAQ is a tourist's guide to the various electronics newsgroups.

Some Comments and Q&A.

Some things to remember. These newsgroups are worldwide in coverage. That means that criticizing someone's English, making nationalistic remarks, personal insults, and criticizing another poster's intelligence are invitations to pointless flame wars.

And the computer equipment that will be used to read these messages is anything but uniform. Any extensions that your computer has to support various character sets will not always be reliably transmitted or displayed at the other end. So avoid fancy superscript characters, degrees temperature, Greek letters, and line drawing characters like the IBM PC extended character set. There are newer standards for indicating the character interpretation to be used with a posting, but there's no guarantee that the person on the other end is up to date.

You should also consider where a poster is when they request the closest source for some product or information. Not everybody has a Radio Shack in the nearest shopping mall. A common problem is that the toll free

800 numbers common in North America are not easily or cheaply accessible from the rest of the world. Look closely at the originators domain address to see if they can contact your recommended source.

Keep in mind that various systems and standards are different around the world. Household power voltages and frequencies are different, and the techniques and regulations to deal with wiring are different enough to cause safety problems if you try to use the wrong one. Video systems (originally tied to the power line frequency) are also widely different around the world. Different scan rates and encoding systems make things incompatible. More recent innovations are even more diverse. For example, stereo audio on television transmissions in the UK, Scandinavian countries, and other parts of Europe is a almost CD quality digital transmission, while in the US, the MTS system is a variation on the analog sub-carrier system used for FM stereo.

Not only are the systems different, so is the jargon used to describe them. What might be a Ground Fault Interrupter in North America, would be a Residual Current Circuit Breaker across the Atlantic. And what was written as 4.7 k ohms, might by (from the requirements of the schematic drafting standards) be given as 4k7 ohms.

Q. "Someone has to give me an answer!"

A. Nope, sorry. Everybody here (except a few salesmen) is doing it for their own purposes, and no question is guaranteed to get an answer. Getting obnoxious about it, or repeating the question across every possible newsgroup, or over and over again won't win any friends and marks you as the archetypical "newbie".

Q. "Just GOOGLE it"

A. If that's going to be your followup post, just shut up and save the bandwidth. By this point in time, (after Google has been running a dozen years), everybody knows about it. At a minium, give the search terms and a critique of a few of the more useful sites that you found in doing that search, with direct URLs.

Q. "What is cross-posting, and is it bad?"

A. Cross-posting is where many discussion group names are included in the "Newsgroups" header of a posting. This causes them to be distributed to each of those newsgroups when they are received and processed at a news server. (Note that Usenet is not like the World Wide Web. In contrast to the Web, postings are distributed worldwide to thousands of separate computer systems, so sending just one message instead of many is beneficial.)

Like many feature of Usenet news, it can be abused. For example, Posting to large numbers of groups at once, or posting to groups that have incompatible discussion topics as a form of harassment. This has gained it a bad reputation that the dogmatic have converted into legendary restrictions.

Try to limit posting to the one newsgroup whose topic matches your subject. If it does seem to overlap a couple of newsgroups' topics, cross-post if you must.

You should avoid multiple postings. This is where you send a separate posting to multiple newsgroups. This causes several bad things. It creates that much more data that each news server system has to process. It starts a separate disconnected discussion thread in each newsgroup. And it causes for anyone who reads many of the newsgroups to see the posting repeated for each group. Any competent newsreader software will only show a cross-posted message to the reader once, but has no way of dealing with these seperate discussion threads.

Q. Are advertisements restricted to ONLY misc.industry.electronics.marketplace?

A. That's the idea.

Q. Why can't I advertise my [stereo/computer/...] for sale in misc.industry.electronics.marketplace?

A. For the main reason the group is for an audience that isn't interested in buying them. (Note the word 'Industry' in the newsgroup name. If you can buy it at the nearest shopping mall, it doesn't belong here). And the second good reason is there are already well established groups for those purposes. Try the groups,,, or

Q. Can I post graphics images to these groups.

A. As a consideration towards small sites and users that use automatic downloading software, the text groups in the big-8 news hierarchies are generally off limits to binary content posts. This is enforced by filtering software at the news servers. Either your posting will get rejected when you try to do this, or it will get dropped when processed as incoming news at another news server. So a large part of your audience will most likely never see it.

Binary content postings are allowed in the alt.binaries hierarchy. The newsgroup alt.binaries.schematics.electronic (Note the usual Usenet reverse polish naming convention) was set up to support postings of images deriving from discussions in the sci.electronics.* and other electronics newsgroups.

If your default news server does not carry the alt.binaries groups (due to the insane traffic volume), there are some free sites with read only acess (see the newsgroup, and there are many commercial NSPs (news service providers) where (by changing the configuration on your news server or browers) you can read and post through them (with an account name and password). [Suggestions?]

Try, for line drawings, to use a compressed file format. Recommended are monochrome .pdf files or and indexed format like GIF or PNG, or TIFF. The smallest files seem to be the formats (mono .pdf, TIFF) that use the Group 4 CCITT fax compression algorithm, with .png and .gif being somewhat bigger. JPG, jpeg doesn't work well on line drawings.

Retention times on alt.binaries may be short, as set by each news servers operation policy. If you have content that has some long term value, try to set up a web site, or ftp directory.

Q. What's the difference between sci.electronic.components, .design, and .equipment?

A. The split here is set up on levels of complexity. In this field of technology, people look for solutions to problems along these levels. Someone who is looking for a box that solves their problems is working at a higher level of detail than someone who is designing a module (circuit board) and that second person is working at a higher level than someone looking for a pre-built integrated circuit that they need to purchase.

The proposed components group is for questions dealing with individual parts. Someone working on this level is looking for a specific function or source or identification for an electronic component. Postings requesting the identification of an integrated circuit are a large portion of the current traffic.

The design group is for persons combining components into circuits. Discussion on design solutions and techniques.

The equipment group is for persons looking for already available solutions to their problems. In other words, if someone is looking for a solution to their problem, and wants to buy something with a warranty, and that has a salesman and tech support along with it, .equipment is the place to ask for advice. (This is not the place to suggest that the person can go down to Radio Shack and get a 555 and wire up a circuit.)

Q. What's left for sci.electronics.misc?

A. Gossip, history, trivia, manufacturing, systems, standards, announcements ...

Charters and description lines.

sci.electronics.basics Elementary questions about electronics.

"A forum for discussion of electronics where there is no such thing as a stupid question. Beginners questions. Discussion of electronics education. Requests for other sources of information."

sci.electronics.cad Schematic drafting, printed circuit layout, simulation.

"sci.electronics.cad is an unmoderated group for the discussion of Computer Aided Design software (and systems) for use in designing electronic circuits and assemblies. Topics can include Schematic "Capture" software, Printed Circuit Board layout software, introductory and educational use of circuit simulation software such as Spice, obtaining simulation descriptions (Spice models) for electronic components, and any other computer software that relates to designing electronic circuits at the printed circuit board level."

sci.electronics.components Integrated circuits, resistors, capacitors.

"Discussions of electronics at the component level. The use, limitations, and identification of resistors, capacitors, integrated circuits, connectors, enclosures, ... and so on. Locations and contact information for Manufacturers, Distributors, and other sources for supply and technical information." Electronic circuit design.

"Discussions relevant to the design of electronics circuits." Test, lab, & industrial electronic products.

"Discussion of the application and internal operation and relative merits of test equipment, laboratory equipment, and industrial equipment. This is not a forsale group. Buying/selling is supposed to occur in the relocated misc.industry.electronics.marketplace group. (Discussions on the relative merits of various consumer electronics equipment are better held in the groups in the rec hierarchy devoted to those topics.)"

sci.electronics.misc General discussions of the field of electronics.

"General discussions on the topic of electronics. (Discussions on the relative merits of various consumer electronics equipment are better held in the groups in the rec hierarchy devoted to those topics.)" Fixing electronic equipment.

" is an unmoderated group for the discussion of repairing electronic equipment. Topics to include: Requests for assistance, Where to obtain servicing information and parts, Techniques for diagnosis and repair, and Anecdotes about success, failures and problems with equipment manufacturers."

misc.industry.electronics.marketplace Electronics products & services.

"Advertisement and discussion for the buying, selling, and bartering of electronic components (integrated circuits, resistor, capacitors, etc.), electronics test equipment, electronics laboratory equipment, electronics industrial equipment, and services used for the production of electronics. NO CONSUMER ELECTRONICS - NO AUDIO, VIDEO, or HOME COMPUTERS."

Other groups of interest

alt.binaries.schematics.electronic sci.engr.electrical.compliance sci.engr.electrical.sys-protection****

Reply to
Mark Zenier

good stuff!

You appear to be misspelling Polish and misusing the term "reverse Polish" I believe ther term you want is "heirachial" or "bass-ackwards"

one way is to serch on (but often it'll find an unsecured server that'll later lock you out)


JPG doesn't woprk as well on line drawings, it's still 1000 times better than posting bmp.

mention of ASCII schematics (which can be posted in any group) and how to read them is notably missing.

discussing the FAQ ? :) (added)


possibly add the following: Posters here should have more than a basic understanding of electronics otherwise ask in S.E.B.

Bye. Jasen

Reply to

Yes, good work, and I hope you can post this FAQ periodically, because it could really help some of the beginners. Once a week would not be too often.

I tried to contact you a while back with no response (don't know why), about the possibility of a FAQ having a number of references to specific areas of interest that many people post questions about on this and other electronic newsgroups. For example, many people ask basic questions about LED's, op-amps, etc.

Let me know if you want to do this, I have a modest start on a groups of links.

I also contacted the fellow from ec3 (forgot his name) that periodically posts information about _searching_ for electronics info, but didn't hear from him either. That could be added.

Reply to
Gary Peek

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