Cathode Ray Tube (CRT)

A cathode ray tube was the main display technology for televisions and monitors before flat screen technologies such as TFT and OLED took over.

It works by having a powerful source of electrons at the back of the evacuated container tube, these are guided by magnetic fields so they travel to a precise location on the front of the tube.

The magnetic field cause the electron beam to move across the screen in a straight line, then move down slightly and move back again. This movement is called a raster.

Special phosphors dots coat the front of the tube and when they are struck by electrons, they light up. Thus forming a display.


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