Why rotary-tip on 4mm banana plugs? - Page 1
Forum section: electronics / testgear

author: MrCAL
author_rank: Newbie
timestamp: September 08, 2024, 09:09:01 am
content: What's the advantage of the rotary-tip on some banana plugs?One might argue it just add one more "problematic" connection-point?Original Fluke prope from model 177. Can actually be unscrewed, which add yet another additional connection-point.I did notice that when you insert the plug with a rotary-tip it does clamps/tightens to it's "body" and make good connection, but still an additional connection compared to the "standard" 4mm banana plug (picture 4)

author: sleemanj
author_rank: Super Contributor
timestamp: September 08, 2024, 09:34:50 am
content: Cheap to manufacture from stamped sheet.The last picture are better (IMHO), they provide a reliable connection every time.I have had too manu bad connections from the springy spinny ones (admittedly cheap ones), I even soldered a batch of them once to stop them spinning because they were so bad.

author: Jeroen3
author_rank: Super Contributor
timestamp: September 08, 2024, 11:47:40 am
content: The stamped metal sheet needs to elongate when inserted. There are some audiofoolery variants around where the flex mechanism is more fixed, but I suspect their mating cycles are a lot less.Being a loose sleeve also makes it much easier to rotate when inserted compared to, for example, the one made from spring pins. (your last picture)

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 12:03:19 pm
content: Quote from: sleemanj on September 08, 2024, 09:34:50 amThe kind in the last picture are only good if it’s good quality product — I have encountered cheap versions of those where the bundle of wires has no springiness and just stays compressed after a few insertions.In a nutshell: any style is fine if it’s high quality, and any style can suck if it’s low quality.

author: daisizhou
author_rank: Super Contributor
timestamp: September 08, 2024, 12:38:01 pm
content: This is the best

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 12:52:09 pm
content: Quote from: daisizhou on September 08, 2024, 12:38:01 pmNope. (Not that one can really call one style the “best” anyway, since it also depends on what you’re mating it with.)Those Pomona-style ones are short, and won’t mate with certain recessed banana plugs that expect the longer “European style” banana plugs. And they’re rated for 15A, while some from Stäubli and Hirschmann (of the lantern style shown in the very first image) can handle 32A.

author: daisizhou
author_rank: Super Contributor
timestamp: September 08, 2024, 01:02:22 pm
content: Quote from: tooki on September 08, 2024, 12:52:09 pmThe best I mean,The banana plug and the shrapnel are integrated, so there is no possibility of poor contact.The author of the first post said that the banana plug has a problem with excessive current and is prone to heat, causing the copper shrapnel to lose its elasticity.

author: electr_peter
author_rank: Unknown
timestamp: September 08, 2024, 01:04:00 pm
content: Quote from: tooki on September 08, 2024, 12:52:09 pmYep, far too short. Exposed metal "ring" near plastic body is useless and make them effectively even shorter still, thus not reliable for many standard sockets. Also, that metal spring is questionable for reliability/low ohmic connection with higher currents.Screw on connection for banana leads is very reliable and adds functionality to plug it in 4mm sockets with no extra* parts (*assuming you don't loose that piece). Other screw on adapters exists.On general banana cables, many connection variants are fine as long as manufacturing quality is good.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 01:17:54 pm
content: Quote from: daisizhou on September 08, 2024, 01:02:22 pmTrue, there are no additional interfaces, but that style doesn’t make as much contact in total as the lantern style.(Also I only assume you’re using machine translation, because “shrapnel” is completely nonsensical in English for any part of a connector.)Quote from: daisizhou on September 08, 2024, 01:02:22 pmUmmm… no they did not. They said nothing of the sort. Someone in areplysaid they had ”bad connections” (without specifying them) withcheap versionsof the lantern-style plugs.High qualitylantern-style plugs do not have that problem, and the lantern style contact is used in high-reliability connectors of all shapes and sizes precisely because it provides some of the best performance of any contact shape. It just needs to be manufactured competently.(I have thrown out cheap versions of the Pomona style ones you like. They were made of cheap metal that deformed after a single insertion, making them useless. I do use real Pomona-branded ones of those, among others.)

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 01:23:32 pm
content: Quote from: electr_peter on September 08, 2024, 01:04:00 pmYep!Sadly, on the Pomona ones daisizhou posted an image of, even on the genuine article (which I have many of), the rear stacking bores are a bit shallowandhave a slightly large inner diameter, so most lantern-style plugs don’t mate with them, because the widest part of the lantern doesn’t make it into the bore!Stupidest thing I ever got was some Pomona clones sold by Mueller, which used lantern-style plugs but with the short Pomona-style body, so they don’t stack with themselves.

author: The Soulman
author_rank: Super Contributor
timestamp: September 08, 2024, 03:20:31 pm
content: I prefer the second style in the first post, but only good quality (hirschmann) ones, I've somehow ended up with a couple "fake" ones I had to solder the "bulge" on one side to obtain a somewhat reliable connection.The type on the third picture I only had bad luck with, including to less "spring" and therefore a sloppy connection and somehow the tips on the end breaking off.

author: The Soulman
author_rank: Super Contributor
timestamp: September 08, 2024, 03:22:25 pm
content: Anyone used these style as sold by ab-precision?

author: axantas
author_rank: Regular Contributor
timestamp: September 08, 2024, 03:54:46 pm
content: The only ones I really rely on are the “Büschel plug connectors” - if they are of good quality. The combination with the removable rotary part are an interesting alternative, but if I can rotate them in mounted state (example two), I do not trust a firm connection.

author: ebastler
author_rank: Super Contributor
timestamp: September 08, 2024, 04:02:41 pm
content: Quote from: MrCAL on September 08, 2024, 09:09:01 amI believe you were not so much asking about the specific shape of the contacts (sheet metal or more massive), but about the fact that it can be unscrewed?Point is, the Fluke tip is not really a banana plug. It is a pointed multimeter probe tip (which you would use most of the time, to probe circuit boards etc.), with the option to screw on a banana adapter (to plug it straight into a power supply or other output jack).

author: The Soulman
author_rank: Super Contributor
timestamp: September 08, 2024, 04:22:40 pm
content: Quote from: ebastler on September 08, 2024, 04:02:41 pmOow, that makes sense, yes, from another brand I've also used crocodile clips and probe extensions that screw on to the probe with the same threads in place of that "banana-bit".So yes, the reason that bit unscrews is to give the same set of probes/leads some more functionality.

author: mawyatt
author_rank: Super Contributor
timestamp: September 08, 2024, 04:27:30 pm
content: Quote from: The Soulman on September 08, 2024, 03:22:25 pmWe have similar types with the Blade Jack. These are OK except one must be very careful inserting in typical DMMs, the blade tips catch the edge of the Copper DMM socket. More of an issue with KS and Keithley than Siglent.Also we've experienced all the issues mentioned with the various types of Banana Plugs/Jacks, even recently having a pair of new Pomona 1269 BNC to Banana Adapters become intermittent. Traced to a contaminated metal connection between the shell and blades on the Banana Jack, Pomona/Fluke Engineering was alerted to this (likely a bad batch).Banana Jacks/Sockets are of many varieties, and many are from cheap sources, some OK, some not. It's a minefield out there wrt to all the various Banana types.Best,

author: tggzzz
author_rank: Super Contributor
timestamp: September 08, 2024, 04:28:44 pm
content: Quote from: The Soulman on September 08, 2024, 03:22:25 pmStaubli SLS4-B SLS4-B/N SLS4-B/E SLS4-B/E/N 30 VAC ~ 60 VDC / max. 19 AI like them after I saw them being used on an HP3458A (albeit in a non-professional setting), by people that do know what they are doing. Stupidly, I didn't ask them why.I hypothesise it is a relatively large contact area, low thermal mass, and gold plating.

author: mawyatt
author_rank: Super Contributor
timestamp: September 08, 2024, 04:38:34 pm
content: Quote from: tggzzz on September 08, 2024, 04:28:44 pmCorrectBest,

author: RoGeorge
author_rank: Super Contributor
timestamp: September 08, 2024, 04:46:51 pm
content: I've always thought that is to help rotating the cable without wearing out the connector.Honestly, don't like them. Also curious what's with all the fruit and animals naming.Banana plugs, crocodiles, parrot-beak hooks, alligator wires, crocodile clamps, etc, etc.

author: IanB
author_rank: Super Contributor
timestamp: September 08, 2024, 04:51:27 pm
content: Quote from: MrCAL on September 08, 2024, 09:09:01 amI very much dislike them for this reason.Quote from: sleemanj on September 08, 2024, 09:34:50 amI soldered all of the spinning cage test leads I have because I got so fed up with the high resistance and unreliable contact. After soldering the connection became very reliable.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 06:23:45 pm
content: Quote from: The Soulman on September 08, 2024, 03:22:25 pmI don’t know who ab-precision is, but the original article made by Stäubli (formerly Multi-Contact), part numbers in tggzzz’s post above, are excellent.In addition to the benefits that tggzzz listed and mawyatt confirmed, they also have the unique ability to be mated plug-to-plugon the male side, since you can just shove one plug into the other, and still use the stacking jacks on the backs. Their light weight also makes them ideal for test leads made of thin wire, so that there isn’t a heavy plug dangling off a thin lead. I used them to make banana-to-DuPont cables, for example. The way that their spring force works makes them fit snugly in basically any jack, yet without being annoyingly hard to use in tight jacks.The downsides are that they only make solder versions of them, and just as mawyatt said, they can snag when inserting them into certain jacks, so careful alignment is sometimes necessary.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 06:25:52 pm
content: Quote from: IanB on September 08, 2024, 04:51:27 pmBut that truly is only ever needed with cheap ones. High quality lantern-style plugs (e.g. Stäubli and Hirschmann) do not suffer from any of those problems, even after decades of use. (I’ve run into ones that are 40+ years old, and they still just work.)

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 06:31:57 pm
content: Quote from: RoGeorge on September 08, 2024, 04:46:51 pmWell, we humans describe things by things we know…(Like how in the Middle Ages, in most European languages, exotic fruits they encountered for the first time were frequently called some kind of “apple”.)Ever watch Dr. Pimple Popper (before she sold out to TLC) or Mr. PopZit? They are always comparing the contents of cysts with foods. 😂 Butter, pudding, mashed potatoes, smoothies, mayonnaise, …And of course we can’t forget the ongoing (for years? Decades?) debate on Wikipedia about alligator clips vs. crocodile clips. Different dialects of English use different terms for different types of clips, unfortunately colliding with two conflicting meanings of crocodile clip.But alligatorwire? Never heard of that!

author: electr_peter
author_rank: Unknown
timestamp: September 08, 2024, 06:49:58 pm
content: Quote from: RoGeorge on September 08, 2024, 04:46:51 pmThere arecrocodileclips anddolphinclips (former long and straight, later with widening near jaw to grab big diameter wires).

author: tggzzz
author_rank: Super Contributor
timestamp: September 08, 2024, 07:32:32 pm
content: Quote from: tooki on September 08, 2024, 06:23:45 pmI'd noticed that back-to-back feature, but haven't found it to be a benefit, as yet.The leads used by the HP3458 owner I mentioned were indeed thin. After all, they weren't going to be carrying much current!

author: MrCAL
author_rank: Newbie
timestamp: September 08, 2024, 09:20:34 pm
content: Quote from: tooki on September 08, 2024, 06:23:45 pmBut perhaps their resistance/voltage-drop are higher than other jacks?The wall/tube seems thin and it's likely made of relatively low-conducting-metal, because it need to have a spring-property, unless they are made of a special copper-alloy-mix? Or will the gold-plating compensate for that?Are they rated just as high? 16-32A?

author: tggzzz
author_rank: Super Contributor
timestamp: September 08, 2024, 09:33:24 pm
content: Quote from: MrCAL on September 08, 2024, 09:20:34 pm19A, at the the voltages I previously noted.Horses for courses; select the coursethenselect the horse.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 11:39:11 pm
content: Quote from: MrCAL on September 08, 2024, 09:20:34 pmTheir maximum current is not as high as the highest-current ones from Stäubli and Hirschmann, but still excellent, as tggzzz said.Their very large contact area, and the fact that the contact itself is quite small (so even if the resistivity is higher, the total resistance is not) means the overall resistance is still very low.Quote from: MrCAL on September 08, 2024, 09:20:34 pmBeryllium copper according to Stäubli. (Good to know, should I ever need to file one down!) So definitelynota low-conductivity metal. (That is a weird assumption to make for a top-quality electrical connector.)Quote from: MrCAL on September 08, 2024, 09:20:34 pmGold is not used as contact plating for its conductivity — copper and silver are much better — but for its resistance to corrosion.

author: coppice
author_rank: Super Contributor
timestamp: September 08, 2024, 11:51:31 pm
content: Quote from: tooki on September 08, 2024, 11:39:11 pmGold plating is not even used when you want really good trouble free contact quality for small signals, such as with microphones, that tolerate a large number of insertion cycles. Things like rhodium alloys are used in places like the BBC where they want contacts that just work.

author: tooki
author_rank: Super Contributor
timestamp: September 08, 2024, 11:56:20 pm
content: I thought rhodium is forhigh-currentcontacts, because that is what gold sucks at. (For example, Apple changed the plating on the Lightning connector — or maybe just on the power pins, I don’t remember — from gold to rhodium precisely because the gold plating was getting blitzed off due to arcing when hot-plugging/unplugging while charging.)My understanding is that different gold alloy platings are used for different applications, including harder ones for high cycle counts.Aaaaahahahhaahhaa the audiophools think rhodium has a “taint” to the sound:https://audioaddictsforum.com/thread/2181/rhodium-plating😂

author: artag
author_rank: Super Contributor
timestamp: September 09, 2024, 12:01:57 am
content: Quote from: tggzzz on September 08, 2024, 07:32:32 pmI encountered them as patch leads on an analogue computer at college. Since patch leads often have to join several nodes, the ability to arbitrarily stack them, as well as their compact size, made them useful.RS components have sold some with a single spring like one of the bunched pins for years. It runs in a groove in the plug. They also sold a stacking version with a screw cable clamp. Staple of many UK schools and labs. The spring is inferior to bunched-pin but pretty effective, though I have found them loose in certain socket types. They seem now to have dropped the stacking type but have similar-looking plugs from Hirschmann with either bunched-pin or lantern contacts.

author: artag
author_rank: Super Contributor
timestamp: September 09, 2024, 12:03:37 am
content: Quote from: tooki on September 08, 2024, 11:56:20 pmLol. Probably even on the (digital) lightning connector.What amuses me is that're worrying about conductivity, which is irrelevant compared with the length of wire it's connected to. What they SHOULD be worrying about is the possibility of a dissimilar metal (or metal/metal oxide) contact that rectifies or is otherwise nonlinear.

author: mawyatt
author_rank: Super Contributor
timestamp: September 09, 2024, 12:34:30 am
content: Quote from: MrCAL on September 08, 2024, 09:20:34 pmAn advantage of these type connectors isn't high current use but their low thermal mass. The Banana Sockets in many Bench DMMs are often much warmer than ambient, so the connector large surface area and thin walled construction allow achieving thermal equilibrium with the sockets quicker than other Banana connector types, which benefits precision measurements.Best,

author: DavidKo
author_rank: Frequent Contributor
timestamp: September 09, 2024, 07:23:40 am
content: I bought them atBürklin.In 4 wire connection I use them on sense wires and high power ones on another pair for easy recognition.

author: Wrenches of Death
author_rank: Regular Contributor
timestamp: September 13, 2024, 03:52:09 am
content: We don't have crocodiles, but this state is ass deep in critters called "alligator mississippiensis". There's somewhere around a couple of million of them running loose here. The snout, jaws, and head of an American alligator are shaped noticeably differently than those of a crocodile. The standard Mueller number 60 clip is an alligator clip. The Mueller number 85 clip is a crocodile clipSince Mueller Electric was the actual inventor of the alligator clip, I would trust their nomenclature of the little beasties.I suspect that if we were ass deep in crocodiles here, they would be called crocodile clips.Oh, and if you're ever in the neighborhood, don't walk around at night without a flashlight!WoD

author: tooki
author_rank: Super Contributor
timestamp: September 13, 2024, 09:29:56 am
content: Yep, totally agree about the terminology! (And having been to north Florida many, many times, I can confirm that gators are everywhere there!)Please fix the quoting in your reply, though. Your reply is inside the quote, and the quote is misattributed.

author: thm_w
author_rank: Super Contributor
timestamp: September 13, 2024, 10:24:53 pm
content: There is also this style, I'm not sure if any major manufacturers make them:The 4th style, IMO, is the best in terms of reliable low contact resistance as far as I've seen. I've had all the other styles degrade over time, even from major manufacturers. These multi spring style ones seem to hold up better? The downside is of course its a bit harder to insert.Here you can see Hirschmann rate them 30A and 3mOhm contact resistance:https://www.reichelt.com/ch/en/shop/product/4_0_mm_bunch_plug_solder_2_5_mm_yellow-106064hah while I was searching I saw this photo:

author: EvgenyG
author_rank: Regular Contributor
timestamp: September 14, 2024, 02:19:10 am
content: Quote from: thm_w on September 13, 2024, 10:24:53 pmI want to second that, I've tried a few different styles and I think this one is the most reliable/durable for the money:DELTRON COMPONENTS 550-0500 (there are variations of part numbers for different colours).It does go in a bit harder but the contact is superior.The OP's type, I was using that one for a while, until the thing snapped inside of the psu and took me hours to get little pieces out.

author: tooki
author_rank: Super Contributor
timestamp: September 14, 2024, 03:54:32 pm
content: I’ve used many of the Deltron 553 series (the stackable banana) and they work well.