Why isnt gold plating on test leads more common? - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: November 07, 2023, 01:28:36 pm
content: You see gold plating on random cables that don't even benefit from it that much all the time. But most of the test leads I've seen haven't had gold plating. Is there a reason for this? it would seem that it's the one place where it would actually be beneficial. For lower contact resistance.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 07, 2023, 02:08:27 pm
content: What test leads?If you're buying clip leads and alligators and stuff from China I got news for 'ya, that ain't even real copper in those wires, you think they're gonna put gold on the connectors?That said, I have some generic clip leads that, at least look gold... Time will tell if they're not just bright beryllium copper (it'll darken in some years).Tim

author: AnalogTodd
author_rank: Regular Contributor
timestamp: November 07, 2023, 02:16:26 pm
content: Quote from: ELS122 on November 07, 2023, 01:28:36 pmThe contact resistance is only part of the concern. Gold plating is used for lower contact resistance mainly because it does not oxidize or react with other materials. Of course, the contact resistance is usually only an issue at high currents, in which case larger connectors/mating surfaces are needed along with larger cabling. That all sounds great, but when it comes to something like test leads, there are other concerns.Test leads are often plugged and unplugged from equipment, unlike connectors that are mated just once or twice and then left alone. Look inside a spacecraft and you'll find a lot of gold-plated connectors. That's because these things get connected and then aren't expected to be pulled apart ever again. The constant connect and disconnect cycle of test leads would mean that you would mechanically abrade the gold plating off the leads. Gold is rather soft and malleable--the surfaces that connect most often would be useless long before the life of the test lead itself is reached and then the benefits of the plating are gone.That leads to the last concern: cost. Gold is far from cheap. I'm sure you can find someone out there who will gold-plate your test leads if you really want it done, but I would fully expect that your final cost may make you cringe.

author: coppercone2
author_rank: Super Contributor
timestamp: November 07, 2023, 02:24:09 pm
content: i love goooolllldddddd

author: coppercone2
author_rank: Super Contributor
timestamp: November 07, 2023, 09:49:16 pm
content: also gold plated test leads are common. the question is how heavy is the gold layer.

author: tooki
author_rank: Super Contributor
timestamp: November 09, 2023, 09:37:58 pm
content: Quote from: AnalogTodd on November 07, 2023, 02:16:26 pmI mean, that’s a sensible theory and all, but unfortunately it’s simply not true.At multiple workplaces here in Switzerland, I’ve encountered banana test leads that have been in heavy use for decades (some upwards of 40 years), with both Multi-Contact (now Stäubli) and Hirschmann gold-plated banana plugs still in excellent condition after all those decades — including the condition of the plating.Is every kind of gold plating suitable for heavy use? No. But it absolutely is possible to make extremely durable gold plating.P.S. Aerospace connectors use heavy gold plating precisely to ensure that they survive high mating cycles.

author: coppercone2
author_rank: Super Contributor
timestamp: November 09, 2023, 09:54:31 pm
content: it also depends on if you clean your equipment connectors and keep them lubricated

author: ArdWar
author_rank: Frequent Contributor
timestamp: November 10, 2023, 03:13:37 am
content: Quote from: AnalogTodd on November 07, 2023, 02:16:26 pmIt's kind of the other way around with connectors. For example look at how Molex rate their connectors. Tin plated connectors have higher current rating but lower mating cycle rating, 25 cycle or so. Gold plated connectors of the same family have slightly lower current rating but significantly higher mating cycle, from 500 up to 5000 cycles.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 10, 2023, 03:34:53 am
content: Quote from: coppercone2 on November 07, 2023, 09:49:16 pmHow thick you mean ?? an 2oz gold tips loll

author: coppercone2
author_rank: Super Contributor
timestamp: November 10, 2023, 04:45:30 am
content: like a gold member

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2023, 08:34:45 am
content: Quote from: coppercone2 on November 09, 2023, 09:54:31 pmIndeed. I just repaired a cable the other day where a conductor had broken, but even testing continuity was initially hampered by the one banana plug being gunked up with who knows what. A good cleaning and some contact grease took care of that. (Given the many, many corroded connectors I’ve seen in my short time working at the chemistry department, I’ve come to the conclusion that this counts as a harsh environment that will benefit from greasing connector contacts as a matter of course.)

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2023, 08:37:42 am
content: Quote from: ELS122 on November 07, 2023, 01:28:36 pmTo answer your actual question “why not?” I’m sure the answer is simply cost. Standard nickel-plated leads are “good enough” for most uses, so manufacturers save the cost.I’m not giving up my gold-plated Probe Master probes, though!

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 10, 2023, 09:07:01 am
content: Quote from: ELS122 on November 07, 2023, 01:28:36 pmAs others have said, primary reason is cost, but to be fair, except for el cheapo hardware, the better rationale is the benefit/cost ratio.Unless you are speaking about flying probes used for automated PCB (or even IC) testing, with typical test probes - the kind you use with multimeters, if that's what you have in mind - the main problem is the quality of the contact between the probe and the surface you are applying it to, rather than the material itself. So unless you pressed very hard with the probe on the other conductor (and made sure the surface was clean), the difference in conductivity of the probe's tip itself will make very little difference in practice.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 10, 2023, 11:38:24 am
content: It will scrape off the sharp pointy top after the first use and then off the rest of the probe within a week.Au plating is usually seen on things that are not subject to abrasion and audiophool components.

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2023, 01:47:11 pm
content: Quote from: Terry Bites on November 10, 2023, 11:38:24 amOther than all the things where none of that is true. In addition to the Stäubli, Hirschmann, and Probe Master stuff I already mentioned, look at the rotary switch of a good-quality handheld multimeter: the PCB switch contacts are gold-plated traces. They’re designed to (and do!) survive thousands of switching cycles. And what about the contacts in USB connectors, the smaller versions of which (micro-b and type C) are designed for thousands of mating cycles, and which always use gold plated contacts?I find it curious that this thread has had multiple people making sweeping proclamations about gold platingfor which counterexamples plainly exist.

author: tszaboo
author_rank: Super Contributor
timestamp: November 10, 2023, 02:03:58 pm
content: Quote from: tooki on November 10, 2023, 01:47:11 pmI don't know. I have very expensive Pomona leads, they don't have gold plating. Nor Agilent or Keithley leads.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 10, 2023, 02:13:57 pm
content: Note that gold itself isn't indicative of quality; thickness and plating process is important. For example the ENIG plating process used for PCBs is unsuitable for connectors. You need so called hard gold, and thick enough coating is expensive.Thick high quality gold plating is an excellent choice for high mating cycle connectors, but not an absolute necessity which is why you also see high quality connectors without gold plating.Claims that gold plating does not withstand many cycles or wears off or is audiophoolery are ridiculous. This forum would be a better place if people who don't have any understanding about a certain topic did not hit the "reply" button; you don't have to. I leave 99% of the threads alone because I feel I don't know about those subjects.

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2023, 02:15:15 pm
content: Quote from: tszaboo on November 10, 2023, 02:03:58 pmAnd? That doesn’t mean that durable gold plating isn’t possible.Pomona (and its parent company, Fluke) do have a few gold-plated DMM probes.

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2023, 02:16:22 pm
content: Quote from: Siwastaja on November 10, 2023, 02:13:57 pmQuoted for truth.

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2023, 02:19:30 pm
content: Quote from: Siwastaja on November 10, 2023, 02:13:57 pmAnd indeed, gold has some characteristics that make it less suitable for certain applications. (As I understand it, it does not resist arcing damage very well, which is why we don’t make gold-plated mains plugs. It’s also why Apple switched away from gold for the Lightning connector: the sparks from unplugging under load were eroding the 5V contact. So they switched to rhodium plating instead.)

author: MarkT
author_rank: Frequent Contributor
timestamp: November 11, 2023, 07:22:25 pm
content: Quote from: Terry Bites on November 10, 2023, 11:38:24 amAbsolutely, (pure) gold is one of the softest metals and will quickly wear off a pointed probe, so it would be pointless (sic). Gold plated contacts in switches have a limited life too, but there the contact pressure is kept low to reduce wear.Besides gold is only a benefit when connecting to something that's also gold, because both parts need to be oxide-free. When probing an oxide-covered surface a sharp point and hard metal probe will push through the surface layer best.Gold is commonly used on high-reliability connectors that have few duty cycles, because its immune to corrosion. And only for signal level, as any arcing will disrupt the plating layer (solid gold contacts are an expensive option!)

author: ywara
author_rank: Contributor
timestamp: November 11, 2023, 11:00:16 pm
content: There's a lot of nonsense in this thread.Gold plating is not expensive. The amount of gold used in plating is incredibly small, but could certainly be a factor when your volumes are in the tens of millions and a a cent or two per part is a major concern.Gold plating is not soft. Hard gold plating is readily available and very durable. Connectors rated for 500-2000 cycles will fail earlier due to worn threads, galling, deformation, and numerous other failure modes long before the gold is compromised at all.Some reasons not to use gold:Best I can tell, gold flash plating does not survive arcing in e.g. relay contacts.Selective plating is insanely difficult and never as successful as overall plating. If you have a PCB-mount connector, you will generally not want gold on the solderable end. Gold is incredibly easy to solder, but it has no particular advantages and can cause gold embrittlement. Do you plate the solder tails with gold or do selective plating (more expensive, harder to do well) with gold and tin?Gold itself is insanely resistant to corrosion, but as plated it is frequently a very porous surface. Gold plated items that need good corrosion resistance are generally plated over heavy nickel layers. Still, due to porosity trapping corrosives, bare nickel tends to do better for corrosion resistance than gold over nickel.It's quite easy to get bad plating adhesion to the underplating with gold. This is a little past my expertise, but if your gold layer flakes off early in the product's lifespan, it's probably not worth doing at all.All in all, I'd guess that test leads (which are a consumable) are not a good place for gold plating. Yes, high quality gold-plated test leads would be better. But, when the test leads are dirt cheap at $20-80 and get abused mechanically where the #1 concern is consistency rather than peak performance, I'd avoid it.

author: coppercone2
author_rank: Super Contributor
timestamp: November 11, 2023, 11:04:27 pm
content: lol wtf is that chatgpt

author: rsjsouza
author_rank: Super Contributor
timestamp: November 12, 2023, 12:33:42 am
content: One more vote to the team "gold FTW". Anyone that works extensively specifying connectors and headers know how gold plated units are specified for a larger number of interconnections during their lifetime when compared to their tinned counterparts. Saying that plating wears off easily is really outside of the realm of reality.

author: coppercone2
author_rank: Super Contributor
timestamp: November 12, 2023, 01:21:58 am
content: and the infamous dave jones eevblog video where he shows you the amount of BS you can run into if you don't have gold plated tips for your probes.