RayTube

A cathode ray tube (CRT) is a vacuum tube containing an electron gun (a source of electrons) and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms (oscilloscope), pictures or alphanumeric characters. CRTs have been largely replaced by newer technologies such as LCDs, but are still used in some applications such as for television sets and oscilloscopes.