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Crocodile clip

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Alligator clip
A crocodile clip manufactured by Mueller Electric. This device is a variation of Dusinberre's original crocodile clip design
Crocodile clips, also called automotive clips, on a set of jumper cables
Three crocodile clips: a bare standard-sized clip; a miniature clip in a yellow plastic boot; a large red Square D multi-function clip

A crocodile clip or alligator clip[1] is a plier-like spring-tensioned metal clip with elongated, serrated jaws that is used for creating a temporary electrical connection. This simple mechanical device gets its name from the resemblance of its serrated jaws to the toothed jaws of a crocodile or alligator. It is used to clamp and grab onto a bare electrical cable to a lead on a battery or some other electrical component. The clip's tapered, serrated jaws are forced together by a spring to grip an object. A Clothespin or Kelvin clip is a special form of crocodile clip whose jaws are insulated from each other, allowing two isolated wires to connect to a single test point. This enables 4-wire measurement of circuits with very low resistances. When manufactured for electronics testing and evaluation, one jaw of the clip is typically permanently crimped or soldered to a wire, or is bent to form the inner tubular contact of a ~4 mm (0.16 in) female banana jack, enabling quick non-permanent connection between a circuit under test and laboratory equipment or to another electrical circuit. The clip is typically covered by a plastic shroud or "boot" to prevent accidental short-circuits.

Small versions, ranging in size from 15–40 mm (0.59–1.57 in) in length, are used in electrical laboratory work.

Large versions of these clips, called automotive clips or battery clamps, are made of solid copper for low electrical resistance, and are used with thick insulated copper cables to make connections between automobile batteries. These jumper cables (a.k.a. 'jump leads') are capable of delivering hundreds of Amperes of current needed to directly power an automobile starter motor, or to transfer energy from a charged lead–acid battery to a discharged one.


Several metal clip designs working on the same principle were patented in the early 20th century: a type of a crocodile clip cutting through the wire insulation was patented by Harry Frankel from New York in 1903,[2] and another design was developed by Westinghouse Electric Corporation engineer[3] George Brown Dusinberre, who patented it in 1909,[4] and later was hired by Ralph S. Mueller & Co.[5] to refine the design, with a later version patented in 1921.[6]


The United States Defense Logistics Agency specifies several types of electrical clips in Commercial Item Description (CID) A-A-59466. In this CID document, crocodile clips are designated type CC, alligator clips are designated types TCx, and other types of electrical clips have various other, unique designations.[7]

Other uses[edit]

  • Dentistry: crocodile clips are often used on the ends of a cord in dental offices to attach a protective bib over the patient's clothing.[8]
  • Laboratory: crocodile clips are frequently used to quickly and cheaply assemble or modify experimental circuits. They are useful for connecting components to wires.
  • Education: like their laboratory use, crocodile clips are sometimes used with batteries, small lightbulbs and other small electrical devices in schools to teach students about electricity.
  • Fencing: crocodile clips are used in fencing to connect to participants' lamé vests to touch-detection systems.
  • Hobby: crocodile clips can be used as miniature clamps to hold items together for gluing or soldering (e.g., Helping hands tool or Clothespin).
  • Camping: crocodile clips may be designed to attach a rope to a tarp or other sheet of material. (While this serves the same purpose as a grommet, it may lead to premature wear at the point of attachment.)
  • Drug use: as a roach clip for holding burning cannabis to avoid burning fingers.
  • Erotic use: as a clamp upon one's nipples for sexual gratification.[9] See nipple clamp for more information on this usage.
  • Film/animation: useful for airborne scenes in possible stop-motion or holding models of any sort in mid air.
  • Electronics: useful as a heat sink while soldering heat-sensitive devices.


  1. ^ "Guide to Clips". Mueller Electric. February 19, 2018. Archived from the original on February 15, 2022. Retrieved February 19, 2018.
  2. ^ U.S. patent 775284A
  3. ^ "Obituary for George Brown DUSINBERRE, 1864-1943". Mansfield Advertiser. 1943-07-28. p. 6. Retrieved 2023-12-20.
  4. ^ U.S. patent 963425A
  5. ^ U.S. patent 1356491A
  6. ^ U.S. patent 1521903A
  7. ^ United States General Services Administration (2011-09-22). "CLIPS, ELECTRICAL, GENERAL SPECIFICATION FOR" (PDF). Retrieved 2017-04-28.
  8. ^ Siddique, Ashik (2013-04-02). "Dental Bib Clips Retain Oral Bacteria After Disinfection". Medical Daily. Retrieved 2022-05-22.
  9. ^ Mandriota, Morgan (18 March 2021). "A Beginner's Guide To Nipple Clamps". Bustle.

External links[edit]

Historical catalogs
Historical patents
Historical trademarks