when did they stop installing knob and tube wiring
Knob-and-tube wiring Knob-and-tube wiring (sometimes abbreviated K&T) is an early standardized method of electrical wiring in buildings, in common use in North America from about 1880 to the 1930s.[1][2] It consisted of single-insulated copper conductors run within wall or ceiling cavities, passing through joist and stud drill-holes via protective porcelain insulating tubes, and supported along their length on nailed-down porcelain knob insulators. Where conductors entered a wiring device such as a lamp or switch, or were pulled into a wall, they were protected by flexible cloth insulating sleeving called loom. The first insulation was asphalt-saturated cotton cloth, then rubber became common. Wire splices in such installations were twisted together for good mechanical strength, then soldered and wrapped with rubber insulating tape and friction tape (asphalt saturated cloth), or made inside metal junction boxes.
Flat panel display The first engineering proposal for a flat-panel TV was by General Electric as a result of its work on radar monitors.[when?] Their publication of their findings gave all the basics of future flat-panel TVs and monitors. But GE did not continue with the R&D required and never built a working flat panel at that time.[1] The first production flat-panel display was the Aiken tube, developed in the early 1950s and produced in limited numbers in 1958. This saw some use in military systems as a heads up display, but conventional technologies overtook its development. Attempts to commercialize the system for home television use ran into continued problems and the system was never released commercially.[2] The Philco Predicta featured a relatively flat (for its day) cathode ray tube setup and would be the first commercially released "flat panel" upon its launch in 1958; the Predicta was a commercial failure. The plasma display panel was invented in 1964 at the University of Illinois, according to The History of Plasma Display Panels.[3] The first active-matrix addressed display was made by T Peter Brody's Thin-Film Devices department at Westinghouse Electric Corporation in 1968.[4] In 1977, James P Mitchell prototyped and later demonstrated what was perhaps the earliest monochromatic flat panel LED television display LED Display. As of 2012[update], 50% of global market share in flat-panel display (FPD) production is by Taiwanese manufacturers such as AU Optronics and Chimei Innolux Corporation.