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  • Early Manufacturers of Telegraph and Electrical Apparatus
    An early list of telegraph and electrical manufacturers T hose who have had the good fortune to come into possession of an early make of telegraph relay, sounder or key are, in many instances, at a loss in trying to establish the date of manufacture of their prize While, in most cases, the instrument bears the name of the manufacturer, there is no clue as to the year in which it was made
  • Telegraph-History
    When the Telegraph Came to California Two articles by James Gamble from The Californian magazine, 1881 : Early Reminiscences of the Telegraph on the Pacific Coast The first telegraph lines in California
  • Insulator (electricity) - Wikipedia
    Physics of conduction in solids Electrical insulation is the absence of electrical conduction Electronic band theory (a branch of physics) says that a charge flows if states are available into which electrons can be excited This allows electrons to gain energy and thereby move through a conductor such as a metal If no such states are available, the material is an insulator
  • U. S. Navy Telegraph Keys: determining the maker and date . . .
    Even the smallest of telegraph key or antique radio collections has at least one and probably several telegraph keys with a long string of letters and numbers
    PART I 50 THE ORIGINAL MORSE TELEGRAPH KEY was actually a notched piece of metal called a Portrule It was pulled along and the parts of the metal that were not notched made contact with another piece of metal, completed the electrical circuit, and produced the dots and dashes of the Morse Code
  • Granville T. Woods - Inventions, Timeline Significance . . .
    Early Inventing Career Living in Cincinnati, Woods eventually set up his own company to develop, manufacture and sell electrical apparatus, and in 1889, he filed his first patent for an improved
  • Submarine communications cable - Wikipedia
    A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea The first submarine communications cables laid beginning in the 1850s carried telegraphy traffic, establishing the first instant telecommunications links between continents, such as the first transatlantic telegraph cable which became
  • Electrical Insulation - Edison Tech Center
    Types and history of electrical insulation 2 ) List of Common Insulating Materials Solids Clay (ceramic)(porcelain) - This is the standard material for high voltage and RF insulators Plastics - PVC, Cresyl Pthalate, DEHP and other plastics replaced rubber as an insulator for wires and other parts PVC and nylon are now standard in most types of wire

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