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Who Invented Television
The scientific principles on which television is based were discovered
in the course of basic research. Only much later were these concepts
applied to television. The first practical television system began
operating in the 1940s.
In 1873 the Scottish scientist James Clerk Maxwell predicted the
existence of the electromagnetic waves that make it possible to transmit
ordinary television broadcasts. Also in 1873 the English scientist
Willoughby Smith and his assistant Joseph May noticed that the electrical
conductivity of the element selenium changes when light falls on it.
This property, known as photoconductivity, is used in the vidicon television
camera tube. In 1888 the German physicist Wilhelm Hallwachs noticed that
certain substances emit electrons when exposed to light. This effect,
called photoemission, was applied to the image-orthicon television camera tube.
Some of the earliest work on television began in 1884; the German
engineer Paul Nipkow designed the first true television mechanism by
passing light through disks that created crude television images.
In 1906, the American engineer Lee De Forest patented the triode vacuum tube.
By 1920 the tube had been improved to the point where it could be used to
amplify electric currents for television.
In the United States inventor John L. Baird used Nipkow’s mechanical
scanner from 1923 to 1925 in experimental television systems. Inventor
Charles F. Jenkins in England also used the same. The pictures were crude but
recognizable. The receiver also used a Nipkow disk placed in front of a lamp
whose brightness was controlled by the signal from the light-sensitive tube
behind the disk in the transmitter. In 1926 Baird demonstrated a television
system that used a 30-hole Nipkow disk. John L. Baird is considered as the
father of television.
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