![]() ![]() The first cathode-ray tube to use a hot cathode was developed by John Bertrand Johnson (who gave his name to the term Johnson noise) and Harry Weiner Weinhart of Western Electric, and became a commercial product in 1922. He expanded on his vision in a speech given in London in 1911 and reported in The Times and the Journal of the Röntgen Society. In 1908, Alan Archibald Campbell-Swinton, fellow of the Royal Society (UK), published a letter in the scientific journal Nature, in which he described how "distant electric vision" could be achieved by using a cathode-ray tube (or "Braun" tube) as both a transmitting and receiving device. Braun was the first to conceive the use of a CRT as a display device. It was a cold-cathode diode, a modification of the Crookes tube with a phosphor-coated screen. ![]() The earliest version of the CRT was known as the "Braun tube", invented by the German physicist Ferdinand Braun in 1897. Thomson succeeded in measuring the charge-mass-ratio of cathode rays, showing that they consisted of negatively charged particles smaller than atoms, the first " subatomic particles", which had already been named electrons by Irish physicist George Johnstone Stoney in 1891. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields, and William Crookes showed they could be deflected by magnetic fields. Hittorf observed that some unknown rays were emitted from the cathode (negative electrode) which could cast shadows on the glowing wall of the tube, indicating the rays were traveling in straight lines.
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