Cathode ray

Streams of electrons emitted by the cathode in a special form of electron tube called a cathode-ray tube (CRT). These electrons are accelerated by the attraction of a positive voltage on special grids called accelerator grids. The cathode rays strike a phosphorescent material that covers the inside of the face of the tube, and when they strike it, the material glows. Cathode-ray tubes are used as the display in computers and oscilloscopes.