Cathode Ray Tube

A cathode ray tube is a vacuum tube containing one or more electron guns that emit electron beams which are directed and controlled to display images on a phosphorescent screen. The images it produces may represent electrical waveforms on an oscilloscope, a frame of video on an analog television set, digital raster graphics on a computer monitor, or other phenomena such as radar targets. A cathode ray tube used inside a television is commonly called a picture tube, and the tubes have also served as memory devices in which the screen is not meant to be seen by an observer. The term cathode ray was first used to describe electron beams before it was understood that what the cathode emitted was a beam of electrons. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/