File:Zworykin and iconoscope.jpg

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Summary

DescriptionZworykin and iconoscope.jpg	English: Russian-American electrical engineer Vladimir Zworykin holding his iconoscope television camera tube around 1950. The iconoscope, developed by Zworykin between 1923 and 1933 at RCA laboratories, was the first successful electronically-scanned television camera tube. It consists of an evacuated glass envelope containing a square photosensitive mica target onto which the image is projected by an external lens. In the light areas of the image, the light knocks electrons off the target surface, discharging it. An electron beam from an electron gun to the side scans the target. Areas which are charged scatter the electron beam, and the current is picked up by a collector electrode. The iconoscope was the main television camera tube used between 1936 and 1946, when it was superseded by the image orthicon.
Date	April 1950
Source	Retrieved May 12, 2014 from Radio-Electronics magazine, Radcraft Publications, Inc., New York, Vol. 21, No. 7, April 1950, p. 61 on American Radio History website
Author	Hugo Gernsback
Permission (Reusing this file)	This 1950 issue of Radio-Electronics magazine would have the copyright renewed in 1978. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1977, 1978 and 1979 show no renewal entries for Radio-Electronics. Therefore the magazine's copyright was not renewed and it is in the public domain.

Licensing

This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.

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