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Thursday, September 13, 2007

Who invented Television?

There was not just one inventor of television. Experiments had been carried out in 1862 by the Abbe Caselli, an Italian priest living in France, who invented a system of transmitting pictures of handmade drawings and written messages.

In 1881 Shelford Bidwell, an Englishman, was able to demonstrate an early form of television which used a cell of selenium (a photoelectric cell) moving up and down mechanically in a box. But he thought that the only way to produce a good picture was to make use of 90,000 photoelectric cells, each attached by a separate wire - and that was beyond him.

A Scottish electrical engineer, Alan Campbell-Swinton, hearing of Bidwell’s experiments and knowing that Ferdinanad Braun, of Austria, had invented the Cathode ray Oscilloscope (rather like a modern television tube, but designed for showing electrical waves), put the two ideas together.
He realised that an electronic switch was needed to switch on the photoelectric cells in turn, and that the oscilloscope tube could be used to receive pictures.

He also designed a camera to go with it, which stored the light falling on to the photoelectric cells so that when it was switched on all the variations of light were transmitted at the same time.
That was in 1911, and became the basis of the television system which went into operation by the BBC at Alexandra Palace, London, in 1936.

Meanwhile, in Russia, Boris Rosing had invented his own television apparatus in 1907 which did not work very well. But one of Rosing’s students, Vladimir Zworykin, left Russia for America in 1919, and invented his camera tube which used Campbell-Swinton’s storage of light principle in 1923. His first pictures were still not very good, but by 1928 he had improved the system considerably.
John Logie Baird, working in London, gave his demonstration of ‘real’television in 1926. This was the first proper television picture ever transmitted, but baird was using a mechanical system instead of an electrical one (although he developed an electronic receiver later).

The race was then on between the RCA Company, of America and Marconi-EMI of England, to develop television. The Marconi-EMI team, under Issac Schoenberg, solved the final problems with the invention of the Emitron camera in 1934.

Meanwhile, John Baird was still working on his television system. In 1928 he produced the first television picture in color rather than in black and white, the high-definition color television picture in 1938, and in 1941 the large screen color television receiver. Unfortunately, he always refused to accept that electronic transmission of pictures was essential, rather than mechanical methods, so none of his inventions are now present in modern television sets.

2 comments:

Mousa December 30, 2008 at 3:10 PM  

the real inventor of tv was hassan kamel alsabah he is lebanese went to usa

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