Wikipedia:Reference desk/Archives/Science/2021 June 9

= June 9 =

Epoxy blob COB on DIP breakout board
What, if anything, is the proper term for COBs put on a breakout board then used in a standard DIP socket? 108.29.92.115 (talk) 08:14, 9 June 2021 (UTC)
 * I think you'll find the answer within the article List of integrated circuit packaging types, which has so many acronyms it is making my head spin (see above on this page at WP:Reference desk/Science). Mike Turnbull (talk) 10:30, 9 June 2021 (UTC)


 * Some more links: COB = chip on board, "breakout board" means a printed circuit board used for prototyping, and DIP = dual in-line package. --Lambiam 10:58, 9 June 2021 (UTC)


 * The OP mentions "epoxy blob" in the header; this makes me thing they are asking about Potting (electronics). -- Jayron 32 13:51, 9 June 2021 (UTC)
 * . Yes, I wondered that too. However, the article I linked to also uses the term epoxy blob in referring to COBs, with, so maybe that's all they needed. Mike Turnbull (talk) 14:28, 9 June 2021 (UTC)
 * If it ain't got that black blob, it ain't a COB. See the pix in our article Chip on board and in the referenced write-up. I do not truly understand the question. To fit in a DIP socket, a component needs matching pins. Are these attached to the PCB on which the chip has been glued? So are the dimensions of the PCB those of a typical DIP package? --Lambiam 09:01, 10 June 2021 (UTC)

Okay trying to restate the question. In some older electronics (usually cheap toys or knockoff handheld videogames from the '90s or early '00s), I semi-frequently run across your standard black epoxy blob COB, but instead of being directly on the device's board it's on a small separate board similar to a surface mount adapter. The adapter is in the form factor of one of the large old 20 or 24-pin DIPs, and usually slotted into a socket. I'm having trouble finding anything about that particular technique (and why it was used since these are cheap devices and it looks to me like it would just increase costs) anywhere on the internet, and was wondering if there's some kind of specific name for it that I'd need to google to find out more. 108.29.92.115 (talk) 08:43, 13 June 2021 (UTC)

Periodic table
If you see a periodic table, this for example (I take this from wikipedia, so no there are any problems of copyright in theory), you see the position of Lantanio and Attinio (I dont know the english name, La and Ac). I am a question about La and Ac, I don't understand if they are members of the group IIIb. Seems yes but I have got indecision. Can you answer me? In what group they appartainment? Thank you --79.30.183.69 (talk) 17:44, 9 June 2021 (UTC)
 * This has been one of the biggest disputes among chemists. The rational thing to do would be to adopt the 32-column periodic table and think of them as group 3 elements while the elements scandium, yttrium, lutetium, and lawrencium are group 17 elements (numbering the groups from 1 to 32.) Georgia guy (talk) 17:51, 9 June 2021 (UTC)
 * We have Group 3 element, with lots of technical analysis of the situation. DMacks (talk) 18:27, 9 June 2021 (UTC)
 * The answer is "whatever is more useful to you". Group 3 element notes that most modern chemists include lutetium and lawrencium as the period 6 and 7 elements in Group III, while older sources may have favored lanthanum and actinium, and some systems include NO period 6 and 7 elements in the group, OR including all of the f-block elements in the group.  The entire point of groups of the periodic table is to keep elements with similar properties together.  In terms of properties, essentially all of the f-block elements share a lot of common properties (part of what made the Lanthanides so hard to isolate is that they are basically chemically and physically indistinguishable from each other).  At some point, someone decided that the electron configuration was the most important thing to consider (and there's really a strong argument to be made that it isn't, but whatever), and spectrographic analysis determined the ground state configuration of lutetium and lawrencium better matched that of scandium and yttrium, but in all honesty, there's not a lot of agreement on the matter.  Ultimately, there periodic table is a tool that helps chemists do their job better, and there's not a lot of lutetium chemistry out there to do; making the matter the wonkiest of chemistry debates; ultimately no one ever really came to an agreement on it because its not that big of a deal.  -- Jayron 32 18:29, 9 June 2021 (UTC)
 * Bunch of interesting sandwich compounds of lutetium, such as Lutetium phthalocyanine, and some tuck-over complexes. "A little niche" might be a nice way to describe it. Lutetium needs some attention. DMacks (talk) 18:48, 9 June 2021 (UTC)
 * There are long discussions in archival Talk pages, for example Talk:Periodic_table/Archive_12 where the few Wikipedia editors for whom the Group 3 question is a big deal have debated the issue. The OP may feel that this is WP:TLDR — and I would agree. Mike Turnbull (talk) 10:35, 10 June 2021 (UTC)
 * See bikeshed effect. -- Jayron 32 16:04, 10 June 2021 (UTC)