Small Kelvin clips that actually grab?

[graybeard]

The smallest one I have seen is this homemade clip.

[precaud]

Yeah, those are awesome. I remember when Rob was doing that project, the hope was some manufacturer would pick up on it and make them... sadly one hasn't.

[precaud]

These ones are new since I last looked:
https://www.ebay.com/itm/283109177832

They are described as "pure copper", gold-plated. The teeth actually look like they could bite. So I ordered a couple sets. If they're steel, he can eat them.

I just got the mini-Kelvin clips referred to above. About 45 days from order to receipt. They are definitely better than previous similar ones I've bought. The contacts are indeed non-ferrous and gold-plated. And the teeth grooves actually are deep enough. Not as deep as I'd like to see but deep enough to grab fairly well. They are still available so I'll be ordering a few more sets just to have around. At this price they're a great deal.

[pope]

Hey, sorry to resurrect this topic but I've also been looking for some good mini kelvin clips with no great success so I'm wondering whether there are more option in 2024.

Unfortunately the ebay links don't work.

[Phil1977]

These ones are not too bad, but in total they are around 4" / 10cm:

https://de.aliexpress.com/item/1005004587014590.html



If it needs to be smaller, 3D-printing may be a literally scalable option:

https://www.thingiverse.com/thing:5606311

[pope]

Thank you Phil,

Unfortunately your aliexpress link doesn't work.

I also found these and I'm tempted to try them out but I found 2-3 sellers  but all of them without great feedback, which is weird. So, I hesitate...

Link 1

Link 2

Link 3

[Phil1977]

Sorry, I hope this link is better:

https://de.aliexpress.com/item/1005004587014590.html

[TopQuark]

I got this set of Kelvin clips to go with my DMM6500. They are made by ETA (ETA4552) and are of high quality.

The cable junctions are over moulded and the spring action of the clips is smooth without being overly strong. The clip tips are serrated reasonably well, and are thin enough to be useful in tight places (e.g. 4 leaded TO-220 precision resistors).

The banana plugs has "SENSE" and "SOURCE" moulded into it, the the sense side of the tip has a small triangle presses into it. Though I still scribbled "SEN" on the sense side of the clip to make things obvious.

Not cheap at 490 RMB (roughly 68 USD), but if you care about making 4-wire measurements with clips, I don't think it gets much better than this. I got mine through taobao ( https://item.taobao.com/item.htm?id=40686646352 ) , so I'm not sure about availability outside of the site's service area.

[pope]

Thanks for the recommendation Topquark!

In fact, I'm looking for BNC ends so I can use them with my RLC meter. I measure L of small coils like the ones shown below and it's a bitch to do it with the normal kelvin clips 

[TopQuark]

Thanks for the recommendation Topquark!

In fact, I'm looking for BNC ends so I can use them with my RLC meter. I measure L of small coils like the ones shown below and it's a bitch to do it with the normal kelvin clips 

Well if you already have a LCR meter, then you'll need the BNC type for sure.

But playing the devil's advocate here, LCR tweezers are definitely the easiest way to go for winding transformers. Bonus points for ease of taking it to the drill press / grinder when grinding the air gap iteratively for flyback coupled inductors. 

[pope]

Thanks for the recommendation Topquark!

In fact, I'm looking for BNC ends so I can use them with my RLC meter. I measure L of small coils like the ones shown below and it's a bitch to do it with the normal kelvin clips 

Well if you already have a LCR meter, then you'll need the BNC type for sure.

But playing the devil's advocate here, LCR tweezers are definitely the easiest way to go for winding transformers. Bonus points for ease of taking it to the drill press / grinder when grinding the air gap iteratively for flyback coupled inductors. 

Well, yeah I thought about tweezers but I need to use the first pin as a reference and then measure the L from pin1 to every other pin. I don't see it happening without a fair amount of swearing... Plus I need to have free hands to go through the menus, etc...

[TopQuark]

Well, yeah I thought about tweezers but I need to use the first pin as a reference and then measure the L from pin1 to every other pin. I don't see it happening without a fair amount of swearing... Plus I need to have free hands to go through the menus, etc...

Well I was trained to use chopsticks before learning how to walk, so as not to starve. So the fact that it is a pair of tweezers but not two metal sticks as probes is an absolute luxury. 

But for real, it is actually quite easy to test different coil pairs with tweezers, but YMMV. 

[pope]

Well, yeah I thought about tweezers but I need to use the first pin as a reference and then measure the L from pin1 to every other pin. I don't see it happening without a fair amount of swearing... Plus I need to have free hands to go through the menus, etc...

Well I was trained to use chopsticks before learning how to walk, so as not to starve. So the fact that it is a pair of tweezers but not two metal sticks as probes is an absolute luxury. 

But for real, it is actually quite easy to test different coil pairs with tweezers, but YMMV. 

Haha, OK fair enough

[shabaz]

Some of the AliExpress Kelvin clips I've tried seem pretty good, not super-robust if accidentally crushed e.g. stepped on! but definitely usable, although there's no real cable strain relief, but that's easy to work around with things like heat-shrink, etc. The ends are not heavily grooved, only lightly, but they stay on unless the cable is tugged. Some LCR meters come with such Kelvin clips, and they work fine.

In terms of physical size, the Mueller Electric BU-75K Kelvin clips are smaller, but more expensive : (
They come with screws (for using with small ring terminals I guess), but it's possible to quickly solder instead (the plastic will melt a bit if not careful), if that's preferred. Main downside is that the screws are still required, because they secure the terminals in place. My solution was to remove the screws, solder the wires, and then put the screws back. The bulge where the wire insulator passes over the screw heads, provides a nice grippy area to hold the clips. That explanation was probably not very good, but hopefully the photo makes it clearer.

The contact ends are pretty flat, not really grooved much, but can stay clipped if no tugging on the leads.