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id stringlengths 40 40	title stringlengths 15 120	text stringlengths 41 3.14k	source stringclasses 2 values
4dad76195dd7ea877dac2986cd31a342b1b20e85	the transformer effect is sometimes used to mitigate	the transformer effect is sometimes used to mitigate the effect of currents induced in the shield. the inner and outer conductors form the primary and secondary winding of the transformer, and the effect is enhanced in some high-quality cables that have an outer layer of mu-metal. because of this 1:1 transformer, the a...	wikipedia
eee2653dae3d4b2ccbcf5ce5603bc9776e739ca6	external fields create a voltage across the inductance	external fields create a voltage across the inductance of the outside of the outer conductor between sender and receiver. the effect is less when there are several parallel cables, as this reduces the inductance and, therefore, the voltage. because the outer conductor carries the reference potential for the signal on t...	wikipedia
4721dd00a3a06d09185c675c5896b446d85359e9	a continuous current, even if small, along the	a continuous current, even if small, along the imperfect shield of a coaxial cable can cause visible or audible interference. in catv systems distributing analog signals the potential difference between the coaxial network and the electrical grounding system of a house can cause a visible "hum bar" in the picture. this...	wikipedia
c5c80e7c193511466d8d3ef9507c4f5a88533ff3	superscreened cables for nuclear use are defined in	superscreened cables for nuclear use are defined in iec 96-4-1, 1990, however as there have been long gaps in the construction of nuclear power stations in europe, many existing installations are using superscreened cables to the uk standard aess(trg) 71181 which is referenced in iec 61917.	wikipedia
90f4287a9d2e6aaa895d143a2f88fcb36274131f	the gaps or holes, allow some of the	the gaps or holes, allow some of the electromagnetic field to penetrate to the other side. for example, braided shields have many small gaps. the gaps are smaller when using a foil (solid metal) shield, but there is still a seam running the length of the cable. foil becomes increasingly rigid with increasing thickness,...	wikipedia
5ab05c763dbf4dfa92f404d3b132ae7c6f0a7ee3	consider the skin effect. the magnitude of an	consider the skin effect. the magnitude of an alternating current in a conductor decays exponentially with distance beneath the surface, with the depth of penetration being proportional to the square root of the resistivity. this means that, in a shield of finite thickness, some small amount of current will still be fl...	wikipedia
8fed1cfff98edcc2b3a708f14cd55cdf4e653c0d	an ideal shield would be a perfect conductor	an ideal shield would be a perfect conductor with no holes, gaps, or bumps connected to a perfect ground. however, a smooth solid highly conductive shield would be heavy, inflexible, and expensive. such coax is used for straight-line feeds to commercial radio broadcast towers. more economical cables must make compromis...	wikipedia
b9e624c5aa347e370c678465088724e401fb0cd3	for example, in the united states, signal leakage	for example, in the united states, signal leakage from cable television systems is regulated by the fcc, since cable signals use the same frequencies as aeronautical and radionavigation bands. catv operators may also choose to monitor their networks for leakage to prevent ingress. outside signals entering the cable can...	wikipedia
79be0445dd7b20c51f840dc6f575132f1568e4d5	signal leakage is the passage of electromagnetic fields	signal leakage is the passage of electromagnetic fields through the shield of a cable and occurs in both directions. ingress is the passage of an outside signal into the cable and can result in noise and disruption of the desired signal. egress is the passage of signal intended to remain within the cable into the outsi...	wikipedia
f4a1f0f8d408c4b6e4c586953c1edefdc5248cd8	all of the components of a coaxial system	all of the components of a coaxial system should have the same impedance to avoid internal reflections at connections between components (see impedance matching). such reflections may cause signal attenuation. they introduce standing waves, which increase losses and can even result in cable dielectric breakdown with hi...	wikipedia
407ec6c8cf36b727ebe5db8243c922cb43e208a3	rg-62 is a 93 Ω coaxial cable originally	rg-62 is a 93 Ω coaxial cable originally used in mainframe computer networks in the 1970s and early 1980s (it was the cable used to connect ibm 3270 terminals to ibm 3274/3174 terminal cluster controllers). later, some manufacturers of lan equipment, such as datapoint for arcnet, adopted rg-62 as their coaxial cable st...	wikipedia
a02d2bb34fabb33da35ef921e6e2181ea64e539a	the arithmetic mean between 30 Ω and 77	the arithmetic mean between 30 Ω and 77 Ω is 53.5 Ω; the geometric mean is 48 Ω. the selection of 50 Ω as a compromise between power-handling capability and attenuation is in general cited as the reason for the number. 50 Ω also works out tolerably well because it corresponds approximately to the feedpoint impedance of...	wikipedia
0a2572c3d887a641b337814b41d48eb8f699ab01	the approximate impedance required to match a centre-fed	the approximate impedance required to match a centre-fed dipole antenna in free space (i.e., a dipole without ground reflections) is 73 Ω, so 75 Ω coax was commonly used for connecting shortwave antennas to receivers. these typically involve such low levels of rf power that power-handling and high-voltage breakdown cha...	wikipedia
5c7777e81e4e42bf64388ec91a7507b297d2fb4d	the best coaxial cable impedances were experimentally determined	the best coaxial cable impedances were experimentally determined at bell laboratories in 1929 to be 77 Ω for low-attenuation, 60 Ω for high-voltage, and 30 Ω for high-power. for a coaxial cable with air dielectric and a shield of a given inner diameter, the attenuation is minimized by choosing the diameter of the inner...	wikipedia
6e838a9967236c47b5a63dd2b6506a1d39335e1b	coaxial connectors are designed to maintain a coaxial	coaxial connectors are designed to maintain a coaxial form across the connection and have the same impedance as the attached cable. connectors are usually plated with high-conductivity metals such as silver or tarnish-resistant gold. due to the skin effect, the rf signal is only carried by the plating at higher frequen...	wikipedia
5173f87804f75ea3f80a893b7239c6d06f07fdab	coaxial cable may be viewed as a type	coaxial cable may be viewed as a type of waveguide. power is transmitted through the radial electric field and the circumferential magnetic field in the tem mode. this is the dominant mode from zero frequency (dc) to an upper limit determined by the electrical dimensions of the cable.	wikipedia
7b7b35074321daeb7da8a72af2f8da3d0f212b2e	in radio-frequency applications up to a few gigahertz,	in radio-frequency applications up to a few gigahertz, the wave propagates primarily in the transverse electric magnetic (tem) mode, which means that the electric and magnetic fields are both perpendicular to the direction of propagation. however, above a certain cutoff frequency, transverse electric (te) or transverse...	wikipedia
adc2cd214103810ce23920e757e5425b21a51f11	twin-lead transmission lines have the property that the	twin-lead transmission lines have the property that the electromagnetic wave propagating down the line extends into the space surrounding the parallel wires. these lines have low loss, but also have undesirable characteristics. they cannot be bent, tightly twisted, or otherwise shaped without changing their characteris...	wikipedia
43f12f011cafd4c82b4a1b0c9c51ddd849d538f9	the insulating jacket can be made from many	the insulating jacket can be made from many materials. a common choice is pvc, but some applications may require fire-resistant materials. outdoor applications may require the jacket to resist ultraviolet light, oxidation, rodent damage, or direct burial. flooded coaxial cables use a water-blocking gel to protect the c...	wikipedia
fd3b1f15bfb7ba22d5d29645af502a1ec1cf549b	while many cables have a solid dielectric, many	while many cables have a solid dielectric, many others have a foam dielectric that contains as much air or other gas as possible to reduce the losses by allowing the use of a larger diameter center conductor. foam coax will have about 15% less attenuation but some types of foam dielectric can absorb moisture—especially...	wikipedia
53ca6346896c9b9e89cfbd67b2a77f4ac230764b	coaxial cables require an internal structure of an	coaxial cables require an internal structure of an insulating (dielectric) material to maintain the spacing between the center conductor and shield. the dielectric losses increase in this order: ideal dielectric (no loss), vacuum, air, polytetrafluoroethylene (ptfe), polyethylene foam, and solid polyethylene. an inhomo...	wikipedia
9b38a959a2dc2cb271f5d2f06bdf27f66a8639e2	for high-power radio-frequency transmission up to about 1	for high-power radio-frequency transmission up to about 1 ghz, coaxial cable with a solid copper outer conductor is available in sizes of 0.25 inch upward. the outer conductor is corrugated like a bellows to permit flexibility and the inner conductor is held in position by a plastic spiral to approximate an air dielect...	wikipedia
00ad25638aadb26e9d6dea026c90bb7cfd56bb03	many conventional coaxial cables use braided copper wire	many conventional coaxial cables use braided copper wire forming the shield. this allows the cable to be flexible, but it also means there are gaps in the shield layer, and the inner dimension of the shield varies slightly because the braid cannot be flat. sometimes the braid is silver-plated. for better shield perform...	wikipedia
9b10915e291bb3623e6ba00f3a967cc0c6f06f3d	the insulator surrounding the inner conductor may be	the insulator surrounding the inner conductor may be solid plastic, a foam plastic, or air with spacers supporting the inner wire. the properties of the dielectric insulator determine some of the electrical properties of the cable. a common choice is a solid polyethylene (pe) insulator, used in lower-loss cables. solid...	wikipedia
2de46e326fe96861365f06456a16aec3fef62d99	coaxial cable design choices affect physical size, frequency	coaxial cable design choices affect physical size, frequency performance, attenuation, power handling capabilities, flexibility, strength, and cost. the inner conductor might be solid or stranded; stranded is more flexible. to get better high-frequency performance, the inner conductor may be silver-plated. copper-plate...	wikipedia
0327482e859a007231d4450d8cf53a3eac1a7fa2	the characteristic impedance of the cable (z) is	the characteristic impedance of the cable (z) is determined by the dielectric constant of the inner insulator and the radii of the inner and outer conductors. in radio frequency systems, where the cable length is comparable to the wavelength of the signals transmitted, a uniform cable characteristic impedance is import...	wikipedia
2ae781d79a2fc8c831f81a4e85b950a16b7b0c5c	coaxial cable conducts electrical signals using an inner	coaxial cable conducts electrical signals using an inner conductor (usually a solid copper, stranded copper or copper-plated steel wire) surrounded by an insulating layer and all enclosed by a shield, typically one to four layers of woven metallic braid and metallic tape. the cable is protected by an outer insulating j...	wikipedia
074df41a730cfd79b602459efca725a6344db7db	coaxial cable is used as a transmission line	coaxial cable is used as a transmission line for radio frequency signals. its applications include feedlines connecting radio transmitters and receivers to their antennas, computer network (e.g., ethernet) connections, digital audio (s/pdif), and distribution of cable television signals. one advantage of coaxial over o...	wikipedia
cfac316941b83829940b31e2d2047c8ae483fb1e	coaxial cable was used in the first (1858)	coaxial cable was used in the first (1858) and following transatlantic cable installations, but its theory was not described until 1880 by english physicist, engineer, and mathematician oliver heaviside, who patented the design in that year (british patent no. 1,407).	wikipedia
790a8080b83c83860e8a3cb7fbd89423e5c919e8	coaxial cable is a type of transmission line,	coaxial cable is a type of transmission line, used to carry high-frequency electrical signals with low losses. it is used in such applications as telephone trunk lines, broadband internet networking cables, high-speed computer data busses, cable television signals, and connecting radio transmitters and receivers to the...	wikipedia
43bbd3afb792221387b0081b029a8159784f71d3	coaxial cable, or coax (pronounced / ˈ k	coaxial cable, or coax (pronounced / ˈ k oʊ. æ k s /), is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating material); many coaxial cables also have a protective outer sheath or jacket. the term coaxial refers to ...	wikipedia
28c2ab42f38a8c8aab2cccd08e56d248034f4106	henry laurence gantt was an american mechanical engineer	henry laurence gantt was an american mechanical engineer and management consultant who is best known for his work in the development of scientific management. he created the gantt chart in the 1910s. gantt charts were employed on major infrastructure projects including the hoover dam and interstate highway system and c...	wikipedia
0ec72e3645529f3b3645c984b08faf404011450a	a novel method of displaying interdependencies of processes	a novel method of displaying interdependencies of processes to increase visibility of production schedules was invented in 1896 by karol adamiecki, which was similar to the one defined by gantt in 1903. however, adamiecki did not publish his works in a language popular in the west; hence gantt was able to popularize a ...	wikipedia
fffdc9030f347695dc8e9f474854815e591b9629	in addition to these technical enhancements, this book	in addition to these technical enhancements, this book also dealt with the broader theme of the obligations of business to society and the particular need for means of reconciling pursuit of profits with the welfare of society. he argued that there needed to be a fair distribution of returns from industry to all segmen...	wikipedia
fa7a43a12f7f69f8164665b3079a8f3d99a39e43	gantt's machine record chart and man record chart	gantt's machine record chart and man record chart are quite similar, though they show both the actual working time for each day and the cumulative working time for a week. each row of the chart corresponds to an individual machine or operator. these charts do not indicate which tasks were to be done, however.	wikipedia
e5cb62d12930ad7dea9a7335ba393e951e8e0092	gantt shows a progress chart that indicates for	gantt shows a progress chart that indicates for each month of the year, using a thin horizontal line, the number of items produced during that month. in addition, a thick horizontal line indicates the number of items produced during the year. each row in the chart corresponds to an order for parts from a specific contr...	wikipedia
dc7cabbe220396e33f82ed208e13733ae8d298c8	in his 1916 book "work, wages, and profits"	in his 1916 book "work, wages, and profits" gantt explicitly discusses scheduling, especially in the job shop environment. he proposes giving to the foreman each day an "order of work" that is an ordered list of jobs to be done that day. moreover, he discusses the need to coordinate activities to avoid "interferences"....	wikipedia
4248e18c9ce1a95c71323c85ad0e6f3ff1398a5b	gantt gives an example with orders that will	gantt gives an example with orders that will require many days to complete. the daily balance has rows for each day and columns for each part or each operation. at the top of each column is the amount needed. the amount entered in the appropriate cell is the number of parts done each day and the cumulative total for th...	wikipedia
cce572a945466726b69d636a800c1484827d7fc9	in 1916, influenced by thorsten veblen gantt set	in 1916, influenced by thorsten veblen gantt set up the new machine, an association which sought to apply the criteria of industrial efficiency to the political process. with the marxist walter polakov he led a breakaway from the 1916 asme conference to call for socializing industrial production under the control of ma...	wikipedia
45a21b978605aed9a8b73dcf475668f9b2405985	in 1911, gantt along with taylor followers frank	in 1911, gantt along with taylor followers frank gilbreth and carl barth founded the society to promote the science of management, later known as the taylor society, to promote taylor's methods and philosophy in industry.	wikipedia