Test your alligator clips

[mockingbird]

So I've been using alligator clips to put a 100Ohm reistor in parallel with a battery voltage measurement with my DMM, and I thought I'd check the continuity on the alligator clips.

Almost all of mine are no good. One of them sort of works, but then fluctuates once you move its wire around. They're all probably oxidized to bits on the inside.

I inherited these from a fellow's wife many years ago, so I never bothered at the time, but I'm glad I did now.

[momaka]

Re: Test your alligator clips

If the alligator clips are crimped to the wires, then it is possible that the wires could have oxidized and are causing a bad connection (especially if they are non-copper wires). Or it could be that the wires are just too old and have gone O/C somewhere.

I bought a bag of small 18 AWG 300V alligator clips from Harbor Freight Tools, and they have been great so far. I think I've had them for over 3 years now. They see lots of use - almost daily. I'm not super gentle with them either. However, they do appear a bit skinny - more like 20 AWG. So I'd take that 18 AWG rating with a grain of salt. Though I will mention that they have sustained currents of 5 Amps without getting even slightly warm. So they aren't awfully terrible either.

[budm]

Re: Test your alligator clips

I remember the good old days when those jumper wires with alligator clips on both ends were made in the USA which the wires are soldered to the clips and the clips have nice strong grip, these day the Chinese made one are all crimped type with very poor crimping. I rework them by soldering the wires to the clips.

[rievax_60]

Re: Test your alligator clips

I always find it necessary to solder in better wire. A real problem I have found lately is that the plastic cover boot goes hard making it more difficult to squeeze the clip open.
I bought some recently on eBay, it is too soon to know if they have the same problem. I have found that the inside of the boot is too slippery. Washing them in turps fixes that.

[mockingbird]

Re: Test your alligator clips

Thansk for the input gentlemen.

Surely enough, I slipped back the shrouds, and the two alligator clips that did work have good professional crimps on the copper (It's not soldered), and they have "Made In Korea" etched into the metal.

All of the other ones only have two teeth at the end which press on the wire, and then they have the copper just shoved behind. It's not a crimp at all. No wonder why none of them work.

There's a hole where the twisted copper strands can go through and theoretically be soldered on the Chinese ones, but that hole is on the part of the clip that you squeeze when you want it to open. So I can see why the Korean ones didn't use this method, because then there would only be a very thin piece of plastic between your finger and the metal. I don't think these Chinese ones are worth the risk.

That's something to add to the shopping list.