Cathode Ray Tube

Electronic television was based on the development of the cathode ray tube.

The development of electronic television systems was based on the development of the cathode ray tube (CRT). A cathode ray tube aka picture tube, was found in all electronic television sets up until the invention of the less bulky LCD screens.

Definitions

• A cathode is a terminal or electrode at which electrons enter a system, such as an electrolytic cell or an electron tube.
• A cathode ray is a stream of electrons leaving the negative electrode, or cathode, in a discharge tube (an electron tube that contains gas or vapor at low pressure), or emitted by a heated filament in certain electron tubes.
• A vacuum tube is an electron tube consisting of a sealed glass or metal enclosure from which the air has been withdrawn.
• A cathode ray tube or CRT is a specialized vacuum tube in which images are produced when an electron beam strikes a phosphorescent surface.

Besides television sets, cathode ray tubes are used in computer monitors, automated teller machines, video game machines, video cameras, oscilloscopes and radar displays.

The first cathode ray tube scanning device was invented by the German scientist Karl Ferdinand Braun in 1897. Braun introduced a CRT with a fluorescent screen, known as the cathode ray oscilloscope. The screen would emit a visible light when struck by a beam of electrons.

Karl Ferdinand Braun

Braun's original cold cathode CRT, 1897

In 1907, the Russian scientist Boris Rosing (who worked with Vladimir Zworykin) used a CRT in the receiver of a television system that at the camera end made use of mirror-drum scanning. Rosing transmitted crude geometrical patterns onto the television screen and was the first inventor to do so using a CRT.

Boris Lvovich Rosing

Vladimir Kosmich Zworykin

Modern phosphor screens using multiple beams of electrons have allowed CRTs to display millions of colors.