The
cathode ray tube (
CRT) is a
vacuum tube containing one or more
electron guns, and a
phosphorescent screen used to view images. It has a means to accelerate and deflect the electron beam(s) onto the screen to create the images. The images may represent electrical
waveforms (
oscilloscope), pictures (
television,
computer monitor),
radar targets or others. CRTs have also been
used as memory devices, in which case the visible light emitted from the fluorescent material (if any) is not intended to have significant meaning to a visual observer (though the visible pattern on the tube face may cryptically represent the stored data).