# Wire

Last updated

A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads or electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Wire gauges come in various standard sizes, as expressed in terms of a gauge number. The term wire is also used more loosely to refer to a bundle of such strands, as in "multistranded wire", which is more correctly termed a wire rope in mechanics, or a cable in electricity.

Structural loads or actions are forces, deformations, or accelerations applied to a structure or its components.

Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. In early days, electricity was considered as being not related to magnetism. Later on, many experimental results and the development of Maxwell's equations indicated that both electricity and magnetism are from a single phenomenon: electromagnetism. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.

Drawing is a metalworking process which uses tensile forces to stretch metal or glass. As the metal is drawn (pulled), it stretches thinner, into a desired shape and thickness. Drawing is classified in two types: sheet metal drawing and wire, bar, and tube drawing. The specific definition for sheet metal drawing is that it involves plastic deformation over a curved axis. For wire, bar, and tube drawing the starting stock is drawn through a die to reduce its diameter and increase its length. Drawing is usually done at room temperature, thus classified a cold working process, however it may be performed at elevated temperatures to hot work large wires, rods or hollow sections in order to reduce forces.

## Contents

Wire comes in solid core, stranded, or braided forms. Although usually circular in cross-section, wire can be made in square, hexagonal, flattened rectangular, or other cross-sections, either for decorative purposes, or for technical purposes such as high-efficiency voice coils in loudspeakers. Edge-wound [1] coil springs, such as the Slinky toy, are made of special flattened wire.

A voice coil is the coil of wire attached to the apex of a loudspeaker cone. It provides the motive force to the cone by the reaction of a magnetic field to the current passing through it. The term is also used for voice coil linear motors, such as those used to move the heads inside hard disk drives, which produce a larger force and move a longer distance but work on the same principle.

A loudspeaker is an electroacoustic transducer; a device which converts an electrical audio signal into a corresponding sound. The most widely used type of speaker in the 2010s is the dynamic speaker, invented in 1925 by Edward W. Kellogg and Chester W. Rice. The dynamic speaker operates on the same basic principle as a dynamic microphone, but in reverse, to produce sound from an electrical signal. When an alternating current electrical audio signal is applied to its voice coil, a coil of wire suspended in a circular gap between the poles of a permanent magnet, the coil is forced to move rapidly back and forth due to Faraday's law of induction, which causes a diaphragm attached to the coil to move back and forth, pushing on the air to create sound waves. Besides this most common method, there are several alternative technologies that can be used to convert an electrical signal into sound. The sound source must be amplified or strengthened with an audio power amplifier before the signal is sent to the speaker.

A coil spring, also known as a helical spring, is a mechanical device which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded.

## History

In antiquity, jewelry often contains, in the form of chains and applied decoration, large amounts of wire that is accurately made and which must have been produced by some efficient, if not technically advanced, means. In some cases, strips cut from metal sheet were made into wire by pulling them through perforations in stone beads. This causes the strips to fold round on themselves to form thin tubes. This strip drawing technique was in use in Egypt by the 2nd Dynasty. From the middle of the 2nd millennium BCE most of the gold wires in jewellery are characterised by seam lines that follow a spiral path along the wire. Such twisted strips can be converted into solid round wires by rolling them between flat surfaces or the strip wire drawing method. The strip twist wire manufacturing method was superseded by drawing in the ancient Old World sometime between about the 8th and 10th centuries AD. [2] There is some evidence for the use of drawing further East prior to this period. [3]

During the growth of the ancient civilizations, ancient technology was the result from advances in engineering in ancient times. These advances in the history of technology stimulated societies to adopt new ways of living and governance.

Egypt, officially the Arab Republic of Egypt, is a country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba and the Red Sea to the east, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, across the Red Sea lies Saudi Arabia, and across the Mediterranean lie Greece, Turkey and Cyprus, although none share a land border with Egypt.

Gold is a chemical element with symbol Au and atomic number 79, making it one of the higher atomic number elements that occur naturally. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Gold often occurs in free elemental (native) form, as nuggets or grains, in rocks, in veins, and in alluvial deposits. It occurs in a solid solution series with the native element silver and also naturally alloyed with copper and palladium. Less commonly, it occurs in minerals as gold compounds, often with tellurium.

Square and hexagonal wires were possibly made using a swaging technique. In this method a metal rod was struck between grooved metal blocks, or between a grooved punch and a grooved metal anvil. Swaging is of great antiquity, possibly dating to the beginning of the 2nd millennium BCE in Egypt and in the Bronze and Iron Ages in Europe for torcs and fibulae. Twisted square-section wires are a very common filigree decoration in early Etruscan jewelry.

Swaging is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.

An anvil is a metalworking tool consisting of a large block of metal, with a flattened top surface, upon which another object is struck.

The Iron Age is the final epoch of the three-age system, preceded by the Stone Age (Neolithic) and the Bronze Age. It is an archaeological era in the prehistory and protohistory of Europe and the Ancient Near East, and by analogy also used of other parts of the Old World. The three-age system was introduced in the first half of the 19th century for the archaeology of Europe in particular, and by the later 19th century expanded to the archaeology of the Ancient Near East. Its name harks back to the mythological "Ages of Man" of Hesiod. As an archaeological era it was first introduced for Scandinavia by Christian Jürgensen Thomsen in the 1830s. By the 1860s, it was embraced as a useful division of the "earliest history of mankind" in general and began to be applied in Assyriology. The development of the now-conventional periodization in the archaeology of the Ancient Near East was developed in the 1920s to 1930s. As its name suggests, Iron Age technology is characterized by the production of tools and weaponry by ferrous metallurgy (ironworking), more specifically from carbon steel.

In about the middle of the 2nd millennium BCE, a new category of decorative tube was introduced which imitated a line of granules. True beaded wire, produced by mechanically distorting a round-section wire, appeared in the Eastern Mediterranean and Italy in the seventh century BCE, perhaps disseminated by the Phoenicians. Beaded wire continued to be used in jewellery into modern times, although it largely fell out of favour in about the tenth century CE when two drawn round wires, twisted together to form what are termed 'ropes', provided a simpler-to-make alternative. A forerunner to beaded wire may be the notched strips and wires which first occur from around 2000 BCE in Anatolia.

The Eastern Mediterranean denotes the countries geographically to the east of the Mediterranean Sea. The Eastern Mediterranean populations share not only geographic position but also cuisine, certain customs and a long, intertwined history.

Phoenicia was a thalassocratic, ancient Semitic-speaking Mediterranean civilization that originated in the Levant, specifically Lebanon, in the west of the Fertile Crescent. Scholars generally agree that it was centered on the coastal areas of Lebanon and included northern Israel, and southern Syria reaching as far north as Arwad, but there is some dispute as to how far south it went, the furthest suggested area being Ashkelon. Its colonies later reached the Western Mediterranean, such as Cádiz in Spain and most notably Carthage in North Africa, and even the Atlantic Ocean. The civilization spread across the Mediterranean between 1500 BC and 300 BC.

Anatolia, also known as Asia Minor, Asian Turkey, the Anatolian peninsula, or the Anatolian plateau, is the westernmost protrusion of Asia, which makes up the majority of modern-day Turkey. The region is bounded by the Black Sea to the north, the Mediterranean Sea to the south, the Armenian Highlands to the east, and the Aegean Sea to the west. The Sea of Marmara forms a connection between the Black and Aegean Seas through the Bosphorus and Dardanelles straits and separates Anatolia from Thrace on the European mainland.

Wire was drawn in England from the medieval period. The wire was used to make wool cards and pins, manufactured goods whose import was prohibited by Edward IV in 1463. [4] The first wire mill in Great Britain was established at Tintern in about 1568 by the founders of the Company of Mineral and Battery Works, who had a monopoly on this. [5] Apart from their second wire mill at nearby Whitebrook, [6] there were no other wire mills before the second half of the 17th century. Despite the existence of mills, the drawing of wire down to fine sizes continued to be done manually.

Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through a single, or series of, drawing die(s). There are many applications for wire drawing, including electrical wiring, cables, tension-loaded structural components, springs, paper clips, spokes for wheels, and stringed musical instruments. Although similar in process, drawing is different from extrusion, because in drawing the wire is pulled, rather than pushed, through the die. Drawing is usually performed at room temperature, thus classified as a cold working process, but it may be performed at elevated temperatures for large wires to reduce forces.

Carding is a mechanical process that disentangles, cleans and intermixes fibres to produce a continuous web or sliver suitable for subsequent processing. This is achieved by passing the fibers between differentially moving surfaces covered with card clothing. It breaks up locks and unorganised clumps of fibre and then aligns the individual fibers to be parallel with each other. In preparing wool fibre for spinning, carding is the step that comes after teasing.

Tintern is a village and community on the west bank of the River Wye in Monmouthshire, Wales, close to the border with England, about 5 miles (8.0 km) north of Chepstow. It is popular with tourists, in particular for the scenery and the ruined Tintern Abbey.

Wire is usually drawn of cylindrical form; but it may be made of any desired section by varying the outline of the holes in the draw-plate through which it is passed in the process of manufacture. The draw-plate or die is a piece of hard cast-iron or hard steel, or for fine work it may be a diamond or a ruby. The object of utilising precious stones is to enable the dies to be used for a considerable period without losing their size, and so producing wire of incorrect diameter. Diamond dies must be rebored when they have lost their original diameter of hole, but metal dies are brought down to size again by hammering up the hole and then drifting it out to correct diameter with a punch.

## Uses

Wire has many uses. It forms the raw material of many important manufacturers, such as the wire netting industry, engineered springs, wire-cloth making and wire rope spinning, in which it occupies a place analogous to a textile fiber. Wire-cloth of all degrees of strength and fineness of mesh is used for sifting and screening machinery, for draining paper pulp, for window screens, and for many other purposes. Vast quantities of aluminium, copper, nickel and steel wire are employed for telephone and data cables, and as conductors in electric power transmission, and heating. It is in no less demand for fencing, and much is consumed in the construction of suspension bridges, and cages, etc. In the manufacture of stringed musical instruments and scientific instruments, wire is again largely used. Carbon and stainless spring steel wire have significant applications in engineered springs for critical automotive or industrial manufactured parts/components. Pin and hairpin making; the needle and fish-hook industries; nail, peg, and rivet making; and carding machinery consume large amounts of wire as feedstock.

Not all metals and metallic alloys possess the physical properties necessary to make useful wire. The metals must in the first place be ductile and strong in tension, the quality on which the utility of wire principally depends. The principal metals suitable for wire, possessing almost equal ductility, are platinum, silver, iron, copper, aluminium, and gold; and it is only from these and certain of their alloys with other metals, principally brass and bronze, that wire is prepared.

By careful treatment, extremely thin wire can be produced. Special purpose wire is however made from other metals (e.g. tungsten wire for light bulb and vacuum tube filaments, because of its high melting temperature). Copper wires are also plated with other metals, such as tin, nickel, and silver to handle different temperatures, provide lubrication, and provide easier stripping of rubber insulation from copper.

Metallic wires are often used for the lower-pitched sound-producing "strings" in stringed instruments, such as violins, cellos, and guitars, and percussive string instruments such as pianos, dulcimers, dobros, and cimbaloms. To increase the mass per unit length (and thus lower the pitch of the sound even further), the main wire may sometimes be helically wrapped with another, finer strand of wire. Such musical strings are said to be "overspun"; the added wire may be circular in cross-section ("round-wound"), or flattened before winding ("flat-wound").

## Production

Wire is often reduced to the desired diameter and properties by repeated drawing through progressively smaller dies, or traditionally holes in draw plates. After a number of passes the wire may be annealed to facilitate more drawing or, if it is a finished product, to maximise ductility and conductivity.

## Finishing, jacketing, and insulating

Electrical wires are usually covered with insulating materials, such as plastic, rubber-like polymers, or varnish. Insulating and jacketing of wires and cables is nowadays done by passing them through an extruder. Formerly, materials used for insulation included treated cloth or paper and various oil-based products. Since the mid-1960s, plastic and polymers exhibiting properties similar to rubber have predominated.

Two or more wires may be wrapped concentrically, separated by insulation, to form coaxial cable. The wire or cable may be further protected with substances like paraffin, some kind of preservative compound, bitumen, lead, aluminum sheathing, or steel taping. Stranding or covering machines wind material onto wire which passes through quickly. Some of the smallest machines for cotton covering have a large drum, which grips the wire and moves it through toothed gears; the wire passes through the centre of disks mounted above a long bed, and the disks carry each a number of bobbins varying from six to twelve or more in different machines. A supply of covering material is wound on each bobbin, and the end is led on to the wire, which occupies a central position relatively to the bobbins; the latter being revolved at a suitable speed bodily with their disks, the cotton is consequently served on to the wire, winding in spiral fashion so as to overlap. If a large number of strands are required the disks are duplicated, so that as many as sixty spools may be carried, the second set of strands being laid over the first.

For heavier cables that are used for electric light and power as well as submarine cables, the machines are somewhat different in construction. The wire is still carried through a hollow shaft, but the bobbins or spools of covering material are set with their spindles at right angles to the axis of the wire, and they lie in a circular cage which rotates on rollers below. The various strands coming from the spools at various parts of the circumference of the cage all lead to a disk at the end of the hollow shaft. This disk has perforations through which each of the strands pass, thence being immediately wrapped on the cable, which slides through a bearing at this point. Toothed gears having certain definite ratios are used to cause the winding drum for the cable and the cage for the spools to rotate at suitable relative speeds which do not vary. The cages are multiplied for stranding with a large number of tapes or strands, so that a machine may have six bobbins on one cage and twelve on the other.

## Forms of wire

### Solid wire

Solid wire, also called solid-core or single-strand wire, consists of one piece of metal wire. Solid wire is useful for wiring breadboards. Solid wire is cheaper to manufacture than stranded wire and is used where there is little need for flexibility in the wire. Solid wire also provides mechanical ruggedness; and, because it has relatively less surface area which is exposed to attack by corrosives, protection against the environment.

### Stranded wire

Stranded wire is composed of a number of small wires bundled or wrapped together to form a larger conductor. Stranded wire is more flexible than solid wire of the same total cross-sectional area. Stranded wire is used when higher resistance to metal fatigue is required. Such situations include connections between circuit boards in multi-printed-circuit-board devices, where the rigidity of solid wire would produce too much stress as a result of movement during assembly or servicing; A.C. line cords for appliances; musical instrument cables; computer mouse cables; welding electrode cables; control cables connecting moving machine parts; mining machine cables; trailing machine cables; and numerous others.

At high frequencies, current travels near the surface of the wire because of the skin effect , resulting in increased power loss in the wire. Stranded wire might seem to reduce this effect, since the total surface area of the strands is greater than the surface area of the equivalent solid wire, but ordinary stranded wire does not reduce the skin effect because all the strands are short-circuited together and behave as a single conductor. A stranded wire will have higher resistance than a solid wire of the same diameter because the cross-section of the stranded wire is not all copper; there are unavoidable gaps between the strands (this is the circle packing problem for circles within a circle). A stranded wire with the same cross-section of conductor as a solid wire is said to have the same equivalent gauge and is always a larger diameter.

However, for many high-frequency applications, proximity effect is more severe than skin effect, and in some limited cases, simple stranded wire can reduce proximity effect. For better performance at high frequencies, litz wire, which has the individual strands insulated and twisted in special patterns, may be used.

### Prefused

Prefused wire is stranded wire made up of strands that are heavily tinned, then fused together. Prefused wire has many of the properties of solid wire, except it is less likely to break. [7]

### Braided wire

A braided wire is composed of a number of small strands of wire braided together. [8] Similar to stranded wires, braided wires are better conductors than solid wires. Braided wires do not break easily when flexed. Braided wires are often suitable as an electromagnetic shield in noise-reduction cables.

### Number of strands

The more individual wire strands in a wire bundle, the more flexible, kink-resistant, break-resistant, and stronger the wire becomes. However, more strands increases manufacturing complexity and cost.

For geometrical reasons, the lowest number of strands usually seen is 7: one in the middle, with 6 surrounding it in close contact. The next level up is 19, which is another layer of 12 strands on top of the 7. After that the number varies, but 37 and 49 are common, then in the 70 to 100 range (the number is no longer exact). Even larger numbers than that are typically found only in very large cables.

For application where the wire moves, 19 is the lowest that should be used (7 should only be used in applications where the wire is placed and then does not move), and 49 is much better. For applications with constant repeated movement, such as assembly robots and headphone wires, 70 to 100 is mandatory.

For applications that need even more flexibility, even more strands are used (welding cables are the usual example, but also any application that needs to move wire in tight areas). One example is a 2/0 wire made from 5,292 strands of #36 gauge wire. The strands are organized by first creating a bundle of 7 strands. Then 7 of these bundles are put together into super bundles. Finally 108 super bundles are used to make the final cable. Each group of wires is wound in a helix so that when the wire is flexed, the part of a bundle that is stretched moves around the helix to a part that is compressed to allow the wire to have less stress.

## Varieties

• Hook-up wire is small-to-medium gauge, solid or stranded, insulated wire, used for making internal connections inside electrical or electronic devices. It is often tin-plated to improve solderability.
• Wire bonding is the application of microscopic wires for making electrical connections inside semiconductor components and integrated circuits.
• Magnet wire is solid wire, usually copper, which, to allow closer winding when making electromagnetic coils, is insulated only with varnish, rather than the thicker plastic or other insulation commonly used on electrical wire. It is used for the winding of motors, transformers, inductors, generators, speaker coils, etc. (For further information about copper magnet wire, see: Copper wire and cable#Magnet wire (Winding wire).).
• Coaxial cable is a cable consisting of an inner conductor, surrounded by a tubular insulating layer typically made from a flexible material with a high dielectric constant, all of which is then surrounded by another conductive layer (typically of fine woven wire for flexibility, or of a thin metallic foil), and then finally covered again with a thin insulating layer on the outside. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. Coaxial cables are often used as a transmission line for radio frequency signals. In a hypothetical ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. Practical cables achieve this objective to a high degree. A coaxial cable provides extra protection of signals from external electromagnetic interference, and effectively guides signals with low emission along the length of the cable which in turn affects thermal heat inside the conductivity of the wire.
• Speaker wire is used to make a low-resistance electrical connection between loudspeakers and audio amplifiers. Some high-end modern speaker wire consists of multiple electrical conductors individually insulated by plastic, similar to Litz wire.
• Resistance wire is wire with higher than normal resistivity, often used for heating elements or for making wire-wound resistors. Nichrome wire is the most common type.

## Notes

1. Swiger Coil Systems. "Edgewound Coils". Swiger Coil Systems, A Wabtec Company. Archived from the original on 19 December 2010. Retrieved 1 January 2011.
2. Jack Ogden, ‘Classical Gold wire: Some Aspects of its Manufacture and Use’, Jewellery Studies, 5, 1991, pp. 95–105.
3. Jack Ogden, ‘Connections between Islam, Europe, and the Far East in the Medieval Period: The Evidence of the Jewelry Technology’. Eds P. Jett, J Douglas, B. McCarthy, J Winter. Scientific Research in the Field of Asian Art. Fiftieth-Anniversary Symposium Proceedings. Archetype Publications, London in association with the Freer Gallery of Art, Smithsonian Institution, 2003.
4. H. R. Schubert, 'The wiredrawers of Bristol' Journal Iron & Steel Institute 159 (1948), 16-22.
5. M. B. Donald, Elizabethan Monopolies: Company of Mineral and Battery Works (Olver & Boyd, Edinburgh 1961), 95-141.
6. D. G. Tucker, 'The seventeenth century wireworks at Whitebrook, Monmouthshire' Bull. Hist. Metall. Gp 7(1) (1973), 28-35.
7. "Types of Strand Construction". Industrial Electric Wire & Cable. 2019. Retrieved February 8, 2019.
8. Hogsett, Jamie; Oehler, Sara (2012-08-29). Show Your Colors: 30 Flexible Beading Wire Jewelry Projects. Kalmbach Books. ISBN   9780871167552.

## Related Research Articles

An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current.

Coaxial cable, or coax, is a type of electrical cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer sheath or jacket. The term coaxial comes from the inner conductor and the outer shield sharing a geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who patented the design in 1880.

Twisted pair cabling is a type of wiring in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted balanced pair, a twisted pair reduces electromagnetic radiation from the pair and crosstalk between neighboring pairs and improves rejection of external electromagnetic interference. It was invented by Alexander Graham Bell.

A braid is a complex structure or pattern formed by interlacing three or more strands of flexible material such as textile yarns, wire, or hair. Compared with the process of weaving, which usually involves two separate, perpendicular groups of strands, a braid is usually long and narrow, with each component strand functionally equivalent in zigzagging forward through the overlapping mass of the others. The most simple and common hair braid is a flat, solid, three-stranded structure. More complex braids can be constructed from an arbitrary number of strands to create a wider range of structures. Some more complex braids are fishtail braid, five-stranded braid, rope braid, French braid and waterfall braid.

American wire gauge (AWG), also known as the Brown & Sharpe wire gauge, is a logarithmic stepped standardized wire gauge system used since 1857, predominantly in North America, for the diameters of round, solid, nonferrous, electrically conducting wire. Dimensions of the wires are given in ASTM standard B 258. The cross-sectional area of each gauge is an important factor for determining its current-carrying ampacity.

Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets and light fittings in a structure.

A power cable is an electrical cable, an assembly of one or more electrical conductors, usually held together with an overall sheath. The assembly is used for transmission of electrical power. Power cables may be installed as permanent wiring within buildings, buried in the ground, run overhead, or exposed.

A shielded cable is an electrical cable of one or more insulated conductors enclosed by a common conductive layer. The shield may be composed of braided strands of copper, a non-braided spiral winding of copper tape, or a layer of conducting polymer. Usually this shield is covered with a jacket. The shield acts as a Faraday cage to reduce electrical noise from affecting the signals, and to reduce electromagnetic radiation that may interfere with other devices.. The shield minimizes capacitively coupled noise from other electrical sources. The shield must be applied across cable splices.

IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables. The current version is Third Edition 2004-11 Among other things, it defines a set of standard wire cross-sectional areas:

Litz wire is a type of specialized multistrand wire or cable used in electronics to carry alternating current (AC) at radio frequencies. The wire is designed to reduce the skin effect and proximity effect losses in conductors used at frequencies up to about 1 MHz. It consists of many thin wire strands, individually insulated and twisted or woven together, following one of several carefully prescribed patterns often involving several levels. The result of these winding patterns is to equalize the proportion of the overall length over which each strand is at the outside of the conductor. This has the effect of distributing the current equally among the wire strands, reducing the resistance. Litz wire is used in high Q inductors for radio transmitters and receivers operating at low frequencies, induction heating equipment and switching power supplies.

Speaker wire is used to make the electrical connection between loudspeakers and audio amplifiers. Modern speaker wire consists of two or more electrical conductors individually insulated by plastic or, less commonly, rubber. The two wires are electrically identical, but are marked to identify the correct audio signal polarity. Most commonly, speaker wire comes in the form of zip cord.

In electrical engineering, an unbalanced line is a transmission line, often coaxial cable, whose conductors have unequal impedances with respect to ground; as opposed to a balanced line. Microstrip and single-wire lines are also unbalanced lines.

Thermoplastic-sheathed cable (TPS) consists of an outer toughened sheath of polyvinyl chloride (PVC) covering one or more individual cables which are PVC insulated annealed copper conductors. It is a commonly used type of wiring for residential and light commercial construction in many countries. The flat version of the cable with two insulated conductors and an uninsulated earth conductor all within the outer sheath is referred to as twin and earth. In mainland Europe, a round equivalent is more common.

Magnet wire or enameled wire is a copper or aluminium wire coated with a very thin layer of insulation. It is used in the construction of transformers, inductors, motors, speakers, hard disk head actuators, electromagnets, and other applications that require tight coils of insulated wire.

Tinsel wire is a type of electrical wire used for applications that require high mechanical flexibility but low current-carrying capacity. Tinsel wire is commonly used in cords of telephones, handsets, headphones, and small electrical appliances. It is far more resistant to metal fatigue failure than either stranded wire or solid wire.

Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor.

A metal hose is a flexible metal line element. There are two basic types of metal hose that differ in their design and application: stripwound hoses and corrugated hoses. Stripwound hoses have a high mechanical strength. Corrugated hoses can withstand high pressure and provide maximum leak tightness on account of their material. Corrugated hoses also exhibit corrosion resistance and pressure tightness under the most extreme conditions, such as in aggressive seawater or at extreme temperatures such as found in space or when transporting cooled liquid gas. They are particularly well suited for conveying hot and cold substances.

Physical media refers to the physical materials that are used to store or transmit information in data communications. These physical media are generally physical objects made of materials such as copper or glass. They can be touched and felt, and have physical properties such as weight and color. For a number of years, copper and glass were the only media used in computer networking.

In electrical engineering, coil winding is the manufacture of electromagnetic coils. Coils are used as components of circuits,and to provide the magnetic field of electrical machines such as motors and generators, and in the manufacture of loudspeakers and microphones. The shape and dimensions of a winding are designed to fulfill the particular purpose. Parameters such as inductance, Q factor, insulation strength, and strength of the desired magnetic field greatly influence the design of coil windings. Coil winding can be structured into several groups regarding the type and geometry of the wound coil. Mass production of electromagnetic coils relies on automated machinery.

## References

•  This article incorporates text from a publication now in the public domain : Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica . 28 (11th ed.). Cambridge University Press. p. 738.