Thursday, June 6, 2019

CRT (Cathode Ray Tube)

CRT (Cathode Ray Tube)

Cathode Ray Tube: – Main part of the Cathode ray terminal is the electron gun. It controlled by an electro magnetic field and the display screen coated by phosphor.

CRT (Cathode Ray Tube)
CRT (Cathode Ray Tube)

Two types of CRT are:

1. Vector CRT Display : – It is the display, in which the electron beam is directed only to places where image is to be created.

2. Raster scan display : - It is the display, in which image is projected on the screen by directing the electron bean across each row of the picture/image elements from top to bottom on the screen.

CRT is similar to big vacuums glass battle. CRT contains three electron guns. The first components of an electron gun in CRT are the heated metal cathode and a contrail grid. Heat is supplied to cathode by directing a current through a coil of wire called the filament, inside the cylindrical cathode structure. This causes electron to be “boiled off” the hat cathode surface. A heated cathode emits a high-speed electron into the phosphor-coated glass screen. The electron gives the energy to the phosphor coated causing it to glow at the point where beam make contact by focusing the electron beam changing its intensity & controlling its purpose of contact against the phosphorus coating through the utilization of device system, the beam can be made to generate a picture/image on the CRT screen.
Components of CRT
Main components of CRT are:

1. Electron Gun:

It is the consisting of a series of components. Primarily a heating filament (heater) and cathode. The electron gun creates a source of electrons which are focused into a narrow beam directed at the face of the CRT.

2. Control electrode:
Control conductor utilized to show the electromagnetic wave on and off.

3. Focusing System:
it is used to create focusing the electron into a narrow beam.

4.Deflection Yoke: -
It is used to manage the direction of the electromagnetic wave. It creates an electric or magnetic field which will bend the electron beam as it passes through the field. In a conventional CRT the yoke is connected to the sweep or scan generator. The deflection yoke which is connected to the sweep generator creates a fluctuating electric or magnetic potential. The change on potential causes the electron beam to be deflected.

5.Phosphorus-coated screen:
Inside front surface of every CRT is coated with phosphorus. Phosphorus glow when they are hit by a high energy electron beam. All phosphorus has a limited life which is a function of both the electron beam and intensity of the electron beam. Phosphorus is the term used to describe the light gives off. By a phosphor after it has been exposed to an electromagnetic wave.

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