An alligator clip (also called a crocodile clip outside of the US) is a spring loaded metal clip that is used for making temporary electrical connections. The name comes from the resemblance to an alligator or crocodile’s jaws as the clip is sometimes serrated with little “teeth”. The clip functions similarly to a clothespin.
See Mueller's Alligator Clip Selection
Finishes:
Alligator Clips can come in many different types of metal and colors. Different metals are sometimes more useful for particular applications, but sometimes it's also just a matter of aesthetics. Read our guide to finishes for help in selecting the right finish.
Some uses are:
Electrical connections: The main use of an alligator clip is for an electrical connection. The clip is attached to components and establishes a connection between the two. Because it’s a clip, it will stay put which frees up the user’s hands.
Laboratory: alligator clips are a cheap easy way to assemble or alter experimental circuits. They are typically used to connect two wires or to connect one wire to the anode or cathode of a device. They are also useful in educational laboratory settings, often used with batteries, lightbulbs, and other devices.
Dentistry: Alligator clips are often used in dental offices on a cord to attach a bib.
Crafts: Alligator clips are used in many hobby and craft activities, including holding items together for soldering or gluing, or making different things out of the clip itself.
ID badges: Alligator clips are often utilized for holding ID badges for conventions and conferences. The clips are on the ends of a lanyard worn around the neck or attached to a front pocket with the clips grabbing onto the badge.
Plier style alligator clips are most commonly used in the automotive industry for battery chargers and jumper cables as well as for welding applications. They come in a variety of sizes and styles and are often insulated for safety and comfort.
A Kelvin or Kelvinized clip is a special plier style clip. The jaws of a Kelvin clip are insulated from each other, allowing 2 isolated wires to connect to a single test point. This is also called Kelvin sensing or four terminal (4T) sensing. This type of connection helps to measure very low resistances and makes a more accurate measurement than traditional testing with just 1 wire (2 terminals).
Some of the first clip designs. The very first model was handmade as were the next two. Dies were utilized to mass produce the next design in 1910. Note the first insulator made in 1910 with a rubber nursing nipple orginally made for baby lambs.
An Ad from 1934 featuring a letter from a farmer who found a new use for the clips. The drawing is by Hal Donahey, a famous cartoonist at the time.
"Farmer Schumacher of Menominee Falls, Wisconsin writes us: - "In regard of your letter that come to me about them clips. Thay are fine and we here on the farm dont wont to be with out them all so the neighbors that got some, but now Ill tell you how we here used them. Put your clips on a little rope about 5 ft long that is longer if the barn is higher. Have a ring on end of rope. Then put a wire from one end of barn to other. Slide your ring of wire as you go along milking from cow to cow. it is better if you have two or more clips then the cow near you can't hurt you eather. We here take clips off after milking is done. But I guess you just as well let them on. Hoping you can unstand what I mean how we here use the clips."
"Is your cow contented? Does she point you out in a crowd with pride? If not, why not use a Universal Clip to hold her tail while milking, so that when the other girls are around she won't have to lower her head and blush guiltily whenever cow-tail holding devices are under discussion."
