History of Tv

Television has become a major industry all over the world, especially in the industrialized nations, and a major medium of communication and source of home entertainment. Television is used in many industries. A few examples are for surveillance in places inaccessible to or dangerous for human beings, in science for tissue microscopy, and in education. Today you can find a television in almost every home. This is why I decided to research the history of the television.

The first television devices were based on an 1884 invention called the scanning disk, patented by Paul Nipkow. This device was a large disk with holes on it, which spun in front of an object while a photoelectric cell recorded changes in light. Depending on the electricity transmitted by the photoelectric cell, an array of light bulbs would glow or remain dark. But Nipkow's mechanical system could not scan and deliver a clear, live-action image. Many inventors hoped to perfect this.

In 1921, a 14-year-old Mormon from Idaho named Philo Farnsworth came up with an idea. While mowing hay in rows, Philo realized an electron beam could scan a picture in horizontal lines, reproducing the image almost instantaneously. Philo was not the only one with this idea. At the same time, Russian immigrant Vladimir Zworykin had also designed a camera that focused an image through a lens onto an array of photoelectric cells coating the end of a tube. The electrical image formed by the cells would be scanned line-by-line by an electron beam and transmitted to a cathode-ray tube.

Rather than an electron beam, Farnsworth's image dissector device used an "anode finger" to scan the picture. An anode finger was a pencil-sized tube with a small aperture at the top. Magnetic coils sprayed the electrons emitted from the electrical image left to right and line-by-line onto the aperture, where they became electric current. Both Zworykin's and Farnsworth's devices then transmitted the current to a cathode-ray tube, which recreated the image by scanning it onto a fluorescent surface.

Farnsworth applied for a patent for his image dissector in 1927. The development of the television system was plagued by lack of money and by challenges Farnsworth's patent from the giant Radio Corporation of America (RCA). In 1934, the British communications company, British Gaumont, bought a license from Farnsworth to make systems based on his designs. In 1939, the American company RCA did the same. Both companies had been developing television systems of their own and recognized Farnsworth as a competitor. World War II interrupted the development of the television. When television broadcasts became a regular occurrence after the war in 1945, Farnsworth was not involved. Instead he decided to devote his time to trying to perfect the devices he had designed.

David Sarnoff, Vice President of the Radio Corporation of America, later hired Vladimir Zworykin to

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