Sourcing the fork terminals used on oscilloscope probe ground leads - Page 1
Forum section: electronics / testgear

author: szszoke
author_rank: Regular Contributor
timestamp: April 28, 2021, 09:31:30 pm
content: Hello!I want to make some alternative ground leads for my oscilloscope probes. I want them to have a test hook instead of a crocodile clip.I would essentially need the fork terminal from cables like these:https://www.mouser.se/ProductDetail/Cal-Test/CT2710-12-0?qs=vgjKjNJexTjNS7asfHV5FA%3D%3DI could technically buy the cables, cut off the crocodile clip, but it feels like a waste of resources.Anyone knows what they are called and where I could buy them (preferable inside the EU)?

author: ebastler
author_rank: Super Contributor
timestamp: April 28, 2021, 09:37:15 pm
content: I don't think there is a size standard for these clips. I have scope probes from Testek, Rigol, and older Hitachis, and they have three different clip sizes. I would buy spare ground leads for your brand of probes.

author: szszoke
author_rank: Regular Contributor
timestamp: April 28, 2021, 09:40:00 pm
content: I have the standard probes that came with my Siglend SDS 1104X-E. The metal part where the fork terminals are connected is 5mm wide.I'm thinking that everybody who makes those cheap oscilloscope probes must source them from somewhere..

author: tautech
author_rank: Super Contributor
timestamp: April 28, 2021, 10:42:14 pm
content: Contact Siglent Germany for the probe accessory pack:https://siglentna.com/product/probe-accessory-kit-pak1/

author: szszoke
author_rank: Regular Contributor
timestamp: April 29, 2021, 07:01:19 am
content: Quote from: tautech on April 28, 2021, 10:42:14 pmI only need the fork connector from the ground lead so that I can solder it onto my own cable.Everything else that is in the pack would be useless for me and buying it would be a waste of resources.

author: ebastler
author_rank: Super Contributor
timestamp: April 29, 2021, 07:06:39 am
content: Yes, we heard you. But apparently you did not hear our replies.

author: tautech
author_rank: Super Contributor
timestamp: April 29, 2021, 07:26:18 am
content: Quote from: szszoke on April 29, 2021, 07:01:19 amThere are other off shelf solutions only dearer.Here's an example of a 500 MHz professional probe I got recently and particularly for the grabber accessory that comes with it however for its cost you could buy 8 probe accessory packs but if you had a 3D printer you might make the flying lead adaptor instead.http://www.pintek.com.tw/customer/pintek/Product/CP-3501R-PRO-b.jpg

author: tautech
author_rank: Super Contributor
timestamp: April 29, 2021, 08:06:30 am
content: Quote from: szszoke on April 28, 2021, 09:31:30 pmMy years old solution was to use grabbers with leads to connect the probe reference lead to and preserve it as intact.Why would that not suit ?Full story from 2014 however I'd built these a few years before:GrabbersA few ideas to stimulate thought......This post refers only to low frequency general fault finding and testing.While scope hook probes are great, therewillbe times when they just won't do the job.Soldering test wires to the DUT can be OK occasionally, but time consuming and frustrating if there are several POI.If you are working on SMD, then you must use other methods to connect.I use Tek grabbers, relatively cheap and versatile, but be mindful of their 40 V max rating.They seem fine for all the SOIC work I have done.They have 25 thou pins and one can easily knock up a selection of leads, with a tinned loop.Have a rummage through your junk pile for wire with the right connectors, knock the shells off and shrink sleeve.To have enough for a 4 Ch scope you would want 5 as a minimum IMO.And if you have more POI's then you could knock up a little test probe header like this.This one is from cheap grabbers off eBay, good quality wire and the header from a 10 mm thick mains switchboard off-cut. Each cable is finished in a loop and glued in a hole, and recessed for safety. The hole is large enough to accommodate a scope hook probe or the reference (GND) lead clip.If I built another, I would use better grabbers and white nylon/plastic for the header to better display the grabber colors that were put on with a Sharpie or highlighter.

author: justanothername
author_rank: Regular Contributor
timestamp: April 29, 2021, 08:21:21 am
content: There is nothing you can't get on aliexpress.https://www.aliexpress.com/item/4000423308252.htmlhttps://www.aliexpress.com/item/4000440166668.htmlhttps://www.aliexpress.com/item/4000516520798.htmlHere is a cheap alternative to the tek grabbers that tautech mentioned. I use them and they are basically the same.https://www.aliexpress.com/item/1005001769970310.html

author: szszoke
author_rank: Regular Contributor
timestamp: April 29, 2021, 05:55:20 pm
content: Quote from: ebastler on April 29, 2021, 07:06:39 amI did. I was just hoping that some might be able to point me towards something that is closer to what I originally wanted.

author: szszoke
author_rank: Regular Contributor
timestamp: April 29, 2021, 08:27:48 pm
content: I think I found something that might be suitable.https://m.aliexpress.com/i/33034313289.htmlThe search term that I used was "crab foot terminal".

author: Electro Fan
author_rank: Super Contributor
timestamp: April 29, 2021, 08:38:43 pm
content: Type in probe ground clip on eBayFor examplehttps://www.ebay.com/itm/222659358233?hash=item33d7882e19:g:tkMAAOSwujBZzKOzhttps://www.ebay.com/itm/391814301240?hash=item5b39f3c638:g:QDwAAOSwHLNZP3brJust examples... might be something else that will fit

author: Ian.M
author_rank: Super Contributor
timestamp: April 29, 2021, 08:43:33 pm
content: There's not much chance of those "crab foot terminals" working - they are too wide to fit in the slot for the ground clip on most probes, and they aren't springy, so will buckle as you force them over the cylindrical ground contact and will then be loose.Bite the bullet: buy a pack of CT2710 or similar ground clip leads, remove the crocodile clips and save them for other uses.

author: ChuckDarwin
author_rank: Regular Contributor
timestamp: April 30, 2021, 07:30:21 am
content: Certainly more expensive than starting from scratch, but consider the Cal Test CT3669-15-8 lead. Same idea as the aligator version but has a 0.6mm pin-jack/socket for connecting grabbers on a 15cm lead. Versatile in the original state and easy to replace the connector with your own if you need to (and shorten the lead). PMK has something similar # 890-400-013 at 11cm with a 0.8mm socket.

author: tooki
author_rank: Super Contributor
timestamp: May 01, 2021, 03:53:43 pm
content: Quote from: ebastler on April 29, 2021, 07:06:39 amIt wasn’t a particularly helpful reply. The question wasn’t “how can I connect something”, it was “where do I get this part”. If you don’t know, replying asecondtime just to insult the OP is truly unnecessary. And you didn’t, and still don’t, know the answer to the OP’s question...

author: ebastler
author_rank: Super Contributor
timestamp: May 01, 2021, 04:19:26 pm
content: Quote from: tooki on May 01, 2021, 03:53:43 pmI beg to differ. In my original reply I had cautioned the OP that there is no standard size for the clips, but that they seem to vary by probe brand. Tautech then recommended a source for complete ground leads, for the brand of probes the OP has. When the OP repeated his "I want just the clips", I felt that he had ignored the prior posts.The "crab foot terminals" the OP then suggested will certainly not work, by the way, as pointed out by Ian.M.

author: tkamiya
author_rank: Super Contributor
timestamp: May 01, 2021, 05:51:33 pm
content: Like this?https://www.amazon.com/Oscilloscope-Ground-Professional-Presision-Accessories/dp/B08LKYXJXX/ref=sr_1_4?dchild=1&keywords=oscilloscope+probe+ground+clip&qid=1619891402&sr=8-4I bought something similar to this and it works with most of my probes. The "clip" part is just a springy metal wire. I can easily adjust to fit the probe.

author: tkamiya
author_rank: Super Contributor
timestamp: May 02, 2021, 05:13:22 pm
content: Oh, you wanted JUST the grabby part that attache to the probes? I really don't think you can buy just that, especially in small quantities. You could get an appropriate material and make them yourself, or have a fab house make it for you. But in the end, they will be far cheaper to buy a set and take it apart.

author: tooki
author_rank: Super Contributor
timestamp: May 02, 2021, 06:34:22 pm
content: Quote from: ebastler on May 01, 2021, 04:19:26 pmHow is him reiterating what hedoeswant, after people repeatedly suggest something he’dexpressly said he didn’t want(right in the original post!) indicative ofhimignoring?!?It’s everyone who suggestedthe very thing he said he didn’twant who were doing the ignoring!!!And then to get snippy with the OP? Ridiculous.In the end, it’s very possible that they aren’t available. But maybe they are, if one doesn’t give up on page 1 of AliExpress search results. Maybe one has to know the exact specific industry name for the part. Is this an elusive part? Absolutely. But the probe manufacturers get them fromsomewhere, after all...

author: tkamiya
author_rank: Super Contributor
timestamp: May 02, 2021, 06:45:34 pm
content: How's this?https://www.digikey.com/en/products/detail/cal-test-electronics/CT3669-15-8/5029189?utm_adgroup=Accessories&utm_source=google&utm_medium=cpc&utm_campaign=Shopping_Product_Test%20and%20Measurement_NEW&utm_term=&utm_content=Accessories&gclid=EAIaIQobChMI2NKM19Or8AIV8wiICR0NAw4rEAQYBSABEgKd__D_BwEhttps://www.amazon.com/Black-PCM-Oscilloscope-Ground-Lead/dp/B016SBD5YCThey are already made and expensive for what they are.... but it does meet OP's needs.As to name, "oscilloscope probe ground CLIP" is the best I can find. At least it returned the most findings.

author: Cerebus
author_rank: Super Contributor
timestamp: May 02, 2021, 06:58:11 pm
content: Quote from: justanothername on April 29, 2021, 08:21:21 amWrong!

author: tkamiya
author_rank: Super Contributor
timestamp: May 02, 2021, 07:09:20 pm
content: Oh, if we are going to go comic route, here's one.https://www.amazon.com/Oscilloscope-Probe-Accessories-Ground-Cable/dp/B086VLQSHL/ref=sr_1_1?dchild=1&keywords=valentine+probe&qid=1619982424&s=industrial&sr=1-1"Valentine's Day Carnival Oscilloscope Probe Accessories?" WoooHooo!https://www.amazon.com/Sexy-Coffee-Mug-Spaceship-Valentine/dp/B084JMPNYX/ref=sr_1_5?dchild=1&keywords=valentine+probe&qid=1619982424&s=industrial&sr=1-5

author: ebastler
author_rank: Super Contributor
timestamp: May 02, 2021, 07:20:58 pm
content: Quote from: tooki on May 02, 2021, 06:34:22 pmtooki, you are conveniently omitting the fact that I had given areasonin my initial reply why I think looking for the individual clips is not a good idea: They come in different sizes, subtle but sufficiently different to ensure that e.g. they are not interchangeable between the three probe brands I have. Hence, even if one finds clips which look plausible, they might not fit. Which is why I recommended to buy complete ground leads for the right brand of probes.You may also have missed the posts the OP and I had written here in the meantime; they unfortunately fell victim to Dave's tinkering with the forum today. I think we had sorted it out. Contrary to what you seem to assume, we are both adults. I am rather baffled why you felt the need to step in and get all excited, and I don't intend to discuss this matter with you any further.

author: tkamiya
author_rank: Super Contributor
timestamp: May 02, 2021, 07:25:07 pm
content: I am not an adult. I won't acknowledge it. It's over rated. At least I don't act like one.

author: tooki
author_rank: Super Contributor
timestamp: May 03, 2021, 03:54:35 am
content: Quote from: ebastler on May 02, 2021, 07:20:58 pmWording it as "conveniently omitting" implies that it's deliberate omission of apertinentfact. But it's not pertinent: while it's perfectly fine to add information like that, itdoesn'tgive you the right to be rude when they choose to not end their search because of it.Quote from: ebastler on May 02, 2021, 07:20:58 pmBecause you wererude.Not a difficult concept to understand.

author: tkamiya
author_rank: Super Contributor
timestamp: May 03, 2021, 04:08:53 am
content: GENTLEMEN!Please stop. Back on topic!

author: jh15
author_rank: Frequent Contributor
timestamp: May 03, 2021, 04:19:07 am
content: * jh15 throws cold water on the mating dogs.

author: tautech
author_rank: Super Contributor
timestamp: May 03, 2021, 04:23:07 am
content: Quote from: jh15 on May 03, 2021, 04:19:07 amGot any magic water to bring back the missing posts ?

author: szszoke
author_rank: Regular Contributor
timestamp: May 03, 2021, 05:44:07 am
content: Quote from: ebastler on May 01, 2021, 04:19:26 pmSeems that my reply is gone..I will try to reconstruct it as much as I can.I'm sorry if my comment made you feel that I'm ignoring what you have said. It wasn't my intention.I will try to explain my point of view hoping that it would help.The same way you thought I ignored the first few replies, I felt that the they did the same with my original question. I felt that I got the typical "it can't be done" answer.There was also the possibility that despite best intentions, you were wrong.From my end I can only assume that you are human. Humans are biased, humans make mistakes, just like I am and I do.At the beginning I was told by two strangers on the internet that something cannot be done the way I want it.I wasn't ready to believe that and change course of my plans.I thank you and everyone else for contributing to my question.Just consider that you and I are different bodies with their own consciousness and whatever confidence you feel about anything you do I have no way of feeling it. Not through writing. Not through a forum that I just joined.As of now, I am still clinging to the idea that I get what I originally asked for.

author: szszoke
author_rank: Regular Contributor
timestamp: May 03, 2021, 05:45:25 am
content: Quote from: tautech on April 29, 2021, 08:06:30 amThis looks promising if it is what I think it is.Would I remove the hook attachment of my probes and plug them into that plastic part with the many holes?

author: ebastler
author_rank: Super Contributor
timestamp: May 03, 2021, 06:50:03 am
content: Quote from: szszoke on May 03, 2021, 05:44:07 amThank you for your comments yesterday, and for taking the time to re-write them!No offense taken here. Yes, your initial very brief response got under my skin a bit, since I felt you were ignoring the information tautech and I had given and were just digging in your heels. I should have resisted the temptation to come back with an equally brief and somewhat blunt response... Sorry about that; I hope we got it sorted now.

author: szszoke
author_rank: Regular Contributor
timestamp: May 03, 2021, 08:32:09 am
content: Quote from: ebastler on May 03, 2021, 06:50:03 amI think we did! It's a bummer that my original response is gone. I think it captured what I wanted to convey a lot better.

author: tautech
author_rank: Super Contributor
timestamp: May 03, 2021, 08:46:57 am
content: Quote from: szszoke on May 03, 2021, 05:45:25 amSorry but I'm reluctant to type another reply and hoping Dave can restore my previous detailed reply.If it doesn't magically reappear I'll see if I can remember all I said.If you Quote that reply and image you can see the thread from whence it came and then go there and download the image files to enlarge them to see the detail better.

author: Cerebus
author_rank: Super Contributor
timestamp: May 03, 2021, 11:13:57 am
content: Quote from: tautech on May 03, 2021, 08:46:57 amI'm afraid it won't now. Dave's restored the forum from backup and then let the system roll forward naturally from there, so anything that happened from between when that backup was taken and when Dave fumbled whatever he fumbled to wreck things will have been permanently lost.

author: wizard69
author_rank: Super Contributor
timestamp: May 04, 2021, 05:41:11 am
content: You might try looking in the catalogs of mechanical suppliers to industry. I mentioned this because Keystones test point jumpers have a very similar form, so a comapny engaged in making such hardware might have something. Unfortunately I did not find anything like that on Keystones web site. The gotcha here is that the clips on the test leads is likely some sort of plated spring steel. The springiness of course to give the clip grip.I could imagine though that a company like Keystone is making the parts on contract. Things like these are almost always contracted out to a job shop that will make a 100,000 in a day and go on to the next contact. This post actually has me wondering about the manufacturing process used, if you really REALLY wanted the clips it might be possible to make a little die to bend the wire into the required form. You might even be able to make the clips by hand with the pliers jewelry makers use to bend and round wire.

author: szszoke
author_rank: Regular Contributor
timestamp: May 04, 2021, 06:12:57 am
content: Quote from: wizard69 on May 04, 2021, 05:41:11 amI also considered making my own to be honest but I was hoping I can just buy them.

author: szszoke
author_rank: Regular Contributor
timestamp: May 04, 2021, 06:22:09 am
content: Quote from: tautech on May 03, 2021, 08:46:57 amThanks for the tip, I tried that, found the original post, but the picture quality didn't improve.Maybe they are "optimized" on the server to reduce disk usage.

author: tautech
author_rank: Super Contributor
timestamp: May 04, 2021, 06:33:29 am
content: Quote from: szszoke on May 04, 2021, 06:22:09 amOk well done.I’ll pop up some more detailed pics soon

author: tautech
author_rank: Super Contributor
timestamp: May 04, 2021, 07:53:01 am
content: Grabber solution in more detail.In a post that was lost I mentioned if I were to make these again instead of fitting grabbers (and these are the cheap and nasty ones that will frustrate the hell out of you by coming unclipped at the slightest movement) I would fit 0.025 female crimps to allow for simple connection to headers or better quality grabbers.Old image from some years back:A tinned loop is made on each lead and housed in a recess that offers some safety at higher voltages and helps ward off Murphy yet the recesses are large enough to permit a probe reference lead clip or probe tip hook to make secure contact with each/any loop.The rear hole is a firm fit to the cable insulation and a tiny drop of epoxy secures each lead in place.I would terminate each lead to 0.025 female crimps if I was to build another so to allow simple connection to grabbers or headers.

author: szszoke
author_rank: Regular Contributor
timestamp: May 04, 2021, 06:59:50 pm
content: Quote from: tautech on May 04, 2021, 07:53:01 amThanks!This looks like something that could work for me!In the meantime, another option that I didn't consider is to find the socket that is inside the hook attechment of the probes and solder them onto wires. Unless they are similarly obtainable as the ground lead clip.

author: tautech
author_rank: Super Contributor
timestamp: May 04, 2021, 07:50:56 pm
content: Quote from: szszoke on May 04, 2021, 06:59:50 pmI would expect they are.Some suitable cheap grabbers:https://www.ebay.com/itm/Goupchn-Mini-Grabber-SMD-IC-Test-Hook-Clip-Jumper-Probe-for-Logical-Analyzer/133521515268

author: tooki
author_rank: Super Contributor
timestamp: May 05, 2021, 11:35:48 pm
content: Quote from: szszoke on May 04, 2021, 06:59:50 pmThat's a much easier thing! Most scope probes have tips that are around 0.5, 0.8, or 1mm diameter. (0.5mm is usually an optional tip, the default is usually 0.8 or 1mm.) The Rigol probes I have are 1mm thick at the base and step down to about 0.75mm. My Testec probes are 0.8mm diameter.Anyhow, what you want is the female contacts for D-sub type connectors. Standard D-sub pins (size 20) are 1.02mm diameter, while D-sub HD pins (size 22) are 0.76mm diameter. You can get them as open barrel crimp contacts, machined closed-barrel crimp contacts, solder cup (for size 20), etc. Ordinary female contacts (stamped or "economy" machined) are essentially split cylinders that spread when a pin is inserted. By applying heat shrink tubing to them after attaching the wire, you not only insulate it, but also provide additional tension on the contact. (There are also more expensive machined sockets that use internal contact baskets. I do not recommend these for this purpose, as you can't reinforce the contact tension, and they cost a lot more anyway.)I have been making myself various test leads using stamped crimp D-sub HD females, as they have proven to be much more resilient in the long term, and work great on standard (0.64mm) square pins, which is my primary use for them. A $20 AliExpress D-sub crimper (such as SN-01B/-02B D-Sub crimper or other small contact crimper like an IWS-3221) will do the job nicely.For the machined ones, you can either solder into them, or use an indent crimper (also available on Ali for ~$35).I've attached a few pix of various contacts that would work. The key is the split-cylinder design that looks kinda like a duck and puts all the contact force right up front, so it'll work even if your probe tip tapers down. I've also added pix showing what a size 22 (HD) female contact looks like when pushed onto the Testec and Rigol probe tips. Even after being slightly overexpanded onto the Rigol, it still holds tight on the Testec.

author: Cerebus
author_rank: Super Contributor
timestamp: May 06, 2021, 12:20:58 am
content: We can do a little better than jury-rigging with crimp connectors, there are BNC adapters made to slip over the ends of scope probes. Make up whatever you want with a BNC (female) on the end, slip an adapter on, and slip the scope probe onto that. If you want grabbers you can find ready made cables with BNC one end and grabbers the other if you don't want to make your own. Pomona make one:This is still jury rigging in one sense, but has the advantage of maintaining coaxiality and a solid connection to the scope probe ground contact.Two different adapters, push fit male BNC one side, socket for the scope probe the other:I've seen them in about 3 different sizes, some from the usual suspects such as KeySight, Tektronix and LeCroy, some from independent connector manufacturers. A search for "scope probe tip bnc adapter" throws up lots.

author: szszoke
author_rank: Regular Contributor
timestamp: May 07, 2021, 06:20:47 am
content: Quote from: tooki on May 05, 2021, 11:35:48 pmHow would you connect the ground lead?

author: szszoke
author_rank: Regular Contributor
timestamp: May 07, 2021, 06:24:24 am
content: Quote from: Cerebus on May 06, 2021, 12:20:58 amThank! I didn't think of this but it looks like a good option as well.I already have a set of probes with these adapters included.I just need to get a female BNC connector.

author: tooki
author_rank: Super Contributor
timestamp: May 07, 2021, 11:07:08 am
content: Quote from: szszoke on May 07, 2021, 06:20:47 amHowever you want. The original hook attachments don’t deal with the ground lead, either, remember?

author: szszoke
author_rank: Regular Contributor
timestamp: May 07, 2021, 01:16:14 pm
content: Quote from: tooki on May 07, 2021, 11:07:08 amBut that is kind of the whole point with my question. I already have a hook attachment for the tip. I wanted one for the ground lead as well.

author: tooki
author_rank: Super Contributor
timestamp: May 07, 2021, 03:48:06 pm
content: Quote from: szszoke on May 07, 2021, 01:16:14 pmThen why did you ask for a source for the hook attachment connector?!?

author: 2N3055
author_rank: Super Contributor
timestamp: May 07, 2021, 03:52:00 pm
content: https://www.tme.eu/hr/en/details/pcm-w3-gnd/accessories-for-oscilloscopes-others/parrot-invent/parrot-pcm-w3-osciloscope-ground-red/

author: Cerebus
author_rank: Super Contributor
timestamp: May 07, 2021, 05:11:20 pm
content: Quote from: tooki on May 07, 2021, 03:48:06 pmHe didn't. You were too busy stoking up an argument with ebastler that you just got it plain arse-backwards.

author: tooki
author_rank: Super Contributor
timestamp: May 07, 2021, 05:54:14 pm
content: Quote from: Cerebus on May 07, 2021, 05:11:20 pmUhhhh... get off your high horse. The question is still quoted everywhere and plainly visible in the post in question:Quote from: szszoke on May 04, 2021, 06:59:50 pmI don’t know how one could interpret it any wayotherthan to mean a socket that attaches to the sharp probe tip itself, since that’s what the hook attachment connects to.

author: szszoke
author_rank: Regular Contributor
timestamp: May 07, 2021, 10:06:01 pm
content: Quote from: tooki on May 07, 2021, 05:54:14 pmI could have worded that better but I don't even know what these parts are called in my native language, let alone English.What I meant there is the kind of socket that is also found on "oscilloscope probe to BNC" adapters.I didn't think someone would misread it because as far as I know, the probe attachment is not secured to the tip pin itself but a bit further back instead, to the body.

author: tooki
author_rank: Super Contributor
timestamp: May 11, 2021, 05:26:49 pm
content: Quote from: szszoke on May 07, 2021, 10:06:01 pmThen why did you talk about the hook?!? The hook attachment contains exactly one contact inside: the female receptacle for the probe tip. How the hook accessory is retained mechanically doesn’t affect this fact either way.