Term of the Moment
APFS
Redirected from: picture tube
Definition: CRT
(1) (C RunTime) See runtime library.
(2) (Cathode Ray Tube) A vacuum tube used as a display screen in an early computer monitor or TV. The viewing end of the tube was coated with phosphors, which emitted light when struck by electrons.
Electrons and Phosphors
The CRT worked by heating a cathode which caused electrons to flow. Accelerating and focusing anodes turned the electrons into a fine beam that was directed to the phosphors by magnetic fields that were generated by steering coils. The viewing end of a color CRT tube was coated with red, green and blue phosphor dots, and separate "electron guns" bombarded their respective colors a line at a time in a prescribed sequence (see raster scan).
Back to the 1800s
The first oscilloscope tube was developed in 1897 by German scientist Ferdinand Braun. Using a fluorescent screen and still known as a "Braun tube" in Germany, his "cathode-ray oscilloscope" was used to display the patterns of electronic signals. Although better known for inventing the CRT, Braun shared the Nobel Prize in 1909 with Guglielmo Marconi for wireless telegraphy.
The Braun Tube - 1897
Bulky But Magic in the 1950s
CRT vs. Flat Panel
CRT Front Projection
CRT Rear Projection
(2) (Cathode Ray Tube) A vacuum tube used as a display screen in an early computer monitor or TV. The viewing end of the tube was coated with phosphors, which emitted light when struck by electrons.
Electrons and Phosphors
The CRT worked by heating a cathode which caused electrons to flow. Accelerating and focusing anodes turned the electrons into a fine beam that was directed to the phosphors by magnetic fields that were generated by steering coils. The viewing end of a color CRT tube was coated with red, green and blue phosphor dots, and separate "electron guns" bombarded their respective colors a line at a time in a prescribed sequence (see raster scan).
Back to the 1800s
The first oscilloscope tube was developed in 1897 by German scientist Ferdinand Braun. Using a fluorescent screen and still known as a "Braun tube" in Germany, his "cathode-ray oscilloscope" was used to display the patterns of electronic signals. Although better known for inventing the CRT, Braun shared the Nobel Prize in 1909 with Guglielmo Marconi for wireless telegraphy.
Using a bellows, it took a strong person to evacuate the air from the tube. The successor to Sir William Crookes' vacuum tubes some 20 years earlier, these tubes used unheated "cold" cathodes that required a huge voltage. (Image courtesy of O'Neill's Electronic Museum.)
Although enormously clunky compared to today's color screens, millions of people were thrilled when they first watched TV on monochrome CRTs. (Image courtesy of Vintage Vibe.)
The CRT gave way to LCD panels in the late 1990s, taking less space, less power and emitting less radiation. This EIZO LCD monitor was state-of-the-art in 1999. (Image courtesy of EIZO Nanao Technologies Inc.)
The first data and TV projectors used CRTs, and although mostly abandoned, they continue to provide high quality. In 2006, this home theater was built by a serious video enthusiast. See front-projection TV. (Images courtesy of Kal of CurtPalme.com.)
Although big and bulky, the Pioneer Elite Pro-107 was perhaps the best CRT-based rear-projection TV ever made. Still working fine after 17 years, this unit was sold for a pittance in 2010. See rear-projection TV.