Types of Propaganda



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Early Discoveries

Chemicals that are conductors of electricity were among the first discoveries leading to the TV. Baron Ȯns Berzelius of Sweden isolated selenium in 1817, and Louis May of Great Britain discovered, in 1873, that the element is a strong electrical conductor. Sir William Crookes invented the cathode ray tube in 1878, but these discoveries took many years to merge into the common ground of television.


Paul Nipkow of Germany made the first crude television in 1884. His mechanical system used a scanning disk with small holes to pick up image fragments and imprint them on a light-sensitive selenium tube. A receiver reassembled the picture. In 1888, W. Hallwachs applied photoelectric cells in cameras; cathode rays were demonstrated as devices for reassembling the image at the receiver by Boris Rosing of Russia and A. A. Campbell-Swinton of Great Britain, both working independently in 1907. Countless radio pioneers including Thomas Edison invented methods of broadcasting television signals.
Although Logie Baird had been developing his own methods of televised images for many years it was in 1924 that he first demonstrated a mechanically scanned television system which transmitted objects in outline and went on the following year to show the head of a dummy, not just in outline but as a real image. First Pictures were shown on Sept 7, 1927.




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