Wow, genuine parts are genuine! - Page 1
Forum section: electronics / general

author: Waxy
author_rank: Newbie
timestamp: April 02, 2025, 05:20:17 pm
content: Hello,So we have this embedded project at work, I have volunteered to design a PCB for automated testing of new changes to firmware. We agreed on the requirements, schematic was made and then design, approved and sent to fab. I went to order few things that we didn't have on hand and when I got to the connectors I started to think about it a bit more.Originally I wanted to just put yours standard 2.54 mm pitch goldpins and call it a day, but since this will be used by "random" people in the lab / server room, it would make sense to use something with a key so that nobody will put it in wrong and fry the thing. I spent an evening looking at the ocean of connectors you can choose from and the only two that made sense for current design (which was at the fab already) were mini-pv/dupoint and Molex's C-Grid III (so 2.54 pitch, and having option for two rows of pins). Mini-pv is not really available from my local distributor so I went with Molex, and thew in a small roll of 22 AWG wire.A bit of tangent, why 2.54 pitch is so... unpopular in connectors? I have seen a plenty of 2.5, but 2.54 is weirdly rare for a kind of "standard" in hobby electronics.So today it all arrived and I started to cobble it all together and... the wire can be bent and actually stays in general shape I give it, I spent few minutes just playing with the connectors like a toddler, it all feels so... sturdy.I guess that after being raised with cheap Chinese electronics and then learning electronics on similarly cheap prototyping gear, the feel of mechanical parts that didn't feel like they were manufactured to the absolute minimum amount of plastic and metal possible, overloaded my autistic brain a bit.That's all, just my thoughts about me being surprised by genuine parts being genuine.Cheers

author: tooki
author_rank: Super Contributor
timestamp: April 02, 2025, 05:56:12 pm
content: 2.54mm pitch... unpopular?!?How did you ever arrive at that idea?It's by far the most common in standard headers and IDC headers. In terms of product lines from the biggest brands (TE/AMP, Amphenol, Molex) there aren't that many productlines, but the number of products isenormous.Of the >300,000 rectangular male headers Digikey has on the website (of all brands, including obsolete items), fullyhalfare 2.54mm. Only about 4000 are 2.50mm.If we look only at the 45,500 ones currently in stock, 24,600 are 2.54mm, and just 2470 are 2.50mm.Here are some of the major 2.54mm lines, without IDC, from the big guys:AMP: AMPMODU, HE13/HE14, MTA-100*Molex: SL, C-Grid, KK254*Amphenol: Mini-PV, Dubox*single-row onlyWithout a doubt, Mini-PV is the most robust of them, in terms of mating cycles. But any of the ones listed here are infinitely more reliable than cheap Chinese Dupont.What certainly is true is that nobody is designingnewconnector lines in 2.54mm — essentially all new connector designs are metric.P.S. You know that Digikey (and likely the other big distributors, like Mouser and Farnell) ships free to Poland on orders above 50 euro/200 złoty, and if you choose UPS, it ships DDP, which means duty and customs are already paid? It'll arrive in just a few days, so no need to limit yourself to what local distributors have on hand. And of course you have TME right in Poland, a huge distributor — and they have Mini-PV in stock at excellent prices.

author: TimFox
author_rank: Super Contributor
timestamp: April 02, 2025, 06:00:37 pm
content: Note that 0.10 inch = 2.54 mm exactly, by American law.

author: Waxy
author_rank: Newbie
timestamp: April 02, 2025, 06:22:22 pm
content: QuoteWell, I'm new in this connector topic. I didn't meant that there small amount of 2.54 mm pitch products, but that looking at the most popular lines I could find, the mini-pv and cgrid are the only ones that I could recognize as your standard 2.54 mm grid typeQuoteThank you, I will use it as a referenceQuoteYea, I know, but you know how it is, you go spend 20 eur, and leave with 200 eur hole in your wallet.And I did bought from TME, but they have all 5 mini-pv connectors, unless I'm looking at it wrong.https://www.tme.eu/pl/en/katalog/industrial-connectors_33/?params=2390:2052239

author: audiotubes
author_rank: Regular Contributor
timestamp: April 02, 2025, 06:47:59 pm
content: Quote from: tooki on April 02, 2025, 05:56:12 pmLast time I looked and bought, Mouser uses only FedEx as their DDP option. It's quite fantastic, if I order on the weekend, Mouser ships Monday morning and it show up here lunchtime Wednesday.

author: tooki
author_rank: Super Contributor
timestamp: April 03, 2025, 09:11:52 am
content: Quote from: audiotubes on April 02, 2025, 06:47:59 pmMakes sense: UPS is DigiKey’s preferred shipper, while FedEx is Mouser’s, so they likely each negotiated DDP terms for Poland only with their preferred shipper. (It varies by country.)

author: tooki
author_rank: Super Contributor
timestamp: April 03, 2025, 09:25:59 am
content: Quote from: Waxy on April 02, 2025, 06:22:22 pmSee also:https://www.mattmillman.com/info/crimpconnectors/Quote from: Waxy on April 02, 2025, 06:22:22 pmWell normally one orders for a whole project, so it’s easy to exceed the minimum, and for the times you don’t, that’s why you keep a list of items that you need, but don’t need urgently, that you can use to “pad” small orders. (And another list of low-priority “wants” for when you’ve run out of items on the “need” list.)Quote from: Waxy on April 02, 2025, 06:22:22 pmI suggest using the manufacturer’s documentation to determine what part numbers you need, then search for those at TME (or on octopart.com to search all the major distributors at once). It’s very common for parts to not have the desired series name in the text, or for it to be spelled differently, or cut off…

author: gbaddeley
author_rank: Regular Contributor
timestamp: April 03, 2025, 01:13:25 pm
content: Quote from: TimFox on April 02, 2025, 06:00:37 pmActually the inch is defined as 0.0254 metres exactly, by international standard. And so is derived from the 1 metre standard. Metric wins in this case!

author: TimFox
author_rank: Super Contributor
timestamp: April 03, 2025, 02:43:02 pm
content: Quote from: gbaddeley on April 03, 2025, 01:13:25 pmThe legal definition in the US is that one yard = 0.9144 meter exactly, since the change in 1959.The rest is arithmetic. Of course in US Customary Units, one yard is exactly 36 inches.An arithmetic calculation from the legal definition is still exact.Do you pronounce it "met-ra", as the pronunciation of the French noun "metre"?