The Cathode Ray Tube i.e. CRT is a type of vacuum tube which contain one or more electron gun which is used to display image on the screen in the form of video signal. The electron beams from the electron gun on the screen having phosphorescent surface to accelerate the beam at high velocity and then deflect it back for creating the images on the phosphorescent screen and then this beam will become visible.
Cathode ray tube working is depending on the movement of electron beam. As these electron guns generate the sharply pointed and focus rays of electron which are accelerated to high voltage, this electron beam which is moving at a high velocity bombarded on the fluorescent screen which create the luminous spot. Thus these beams from the electron gun pass from the pair of electrostatic deflection plate. This electrostatic plate will deflect the beam when the voltage is applied to it. As soon as voltage is applied the pair of the plate will move the beam of ray in two partitions, one will move in upward direction and other part of plate move the beam from one side to another. These vertical and horizontal movements of electron are independent to each other because of which the position of electron beam will visible anywhere on the screen.
Construction of CRT
The main parts of this Cathode Ray Tube are
- Electron gun
- Focusing and accelerating anodes
- Electrostatic deflection plates
- Evacuated glass envelop
- Electron Gun- As we discussed this electron gun is used for produced high velocity accelerated electrons.
- Focusing and Accelerating Anode- this component is used for the production of a narrow and sharply focus beam of electrons.
- Electrostatic Deflection Plates- horizontal and vertical deflection plates are used for controlling the flow and path of the beams.
- Evacuated Glass Envelope- this is used for electrons to travel freely from one end to another also with a phosphorescent screen which is used to produce bright spot when the high velocity electron beams strike on it.
Application of CRT
- In computer monitors
- Televisions
- For display device in radar
- In cathode ray oscilloscope