Significations et usages de coiling

A coil is a series of loops. A coiled coil is a structure in which the coil itself is in turn also looping.

  Electromagnetic coils

  Diagram of typical transformer configurations

An electromagnetic coil (or simply a "coil") is formed when a conductor (usually an insulated solid copper wire) is wound around a core or form to create an inductor or electromagnet. One loop of wire is usually referred to as a turn, and a coil consists of one or more turns. For use in an electronic circuit, electrical connection terminals called taps are often connected to a coil. Coils are often coated with varnish or wrapped with insulating tape to provide additional insulation and secure them in place. A completed coil assembly with taps is often called a winding. A transformer is an electromagnetic device that has a primary winding and a secondary winding that transfers energy from one electrical circuit to another by inductive coupling without moving parts. The term tickler coil usually refers to a feedback coil, which is often the third coil placed in relation to a primary coil and secondary coil. A coil tap is a wiring feature found on some electrical transformers, inductors and coil pickups, all of which are sets of wire coils. The coil tap(s) are points in a wire coil where a conductive patch has been exposed (usually on a loop of wire that extends out of the main coil body). As self induction is larger for larger coil diameter the current in a thick wire tries to flow on the inside. The ideal use of copper is achieved by foils. Sometimes this means that a spiral is a better alternative. Multilayer coils have the problem of interlayer capacitance, so when multiple layers are needed the shape needs to be radically changed to a short coil with many layers so that the voltage between consecutive layers is smaller (making them more spiral like).

  Nikola Tesla's flat spiral coil.

  Analysis

See Inductor

  Further reading

• Querfurth, William, "Coil winding; a description of coil winding procedures, winding machines and associated equipment for the electronic industry" (2d ed.). Chicago, G. Stevens Mfg. Co., 1958.
• Weymouth, F. Marten, "Drum armatures and commutators (theory and practice) : a complete treatise on the theory and construction of drum winding, and of commutators for closed-coil armatures, together with a full résumé of some of the principal points involved in their design; and an exposition of armature reactions and sparking". London, "The Electrician" Printing and Publishing Co., 1893.
• "Coil winding proceedings". International Coil Winding Association.
• Chandler, R. H., "Coil coating review, 1970-76". Braintree, R. H. Chandler Ltd, 1977.

  External links

Look up coil or winding in Wiktionary, the free dictionary.

• R. Clarke, "Producing wound components". Surrey.ac.uk, 2005 October 9