Display Devices in Computer Graphics

The most prominent part of a personal computer is the display system that is responsible for graphics display. The display system may be attached to a PC to display character, picture, and video output. The display systems are often referred to as Video Display Unit (VDU) or Monitor.

Cathode Ray Tube (CRT):

A CRT is like as a big vacuum glass bottle. It contains three electron guns that squirt out a focused beam of electrons, deflection electrostatic which deflects the beams both up and down and side-wise and a phosphor-coated screen upon which these beams.


The primary component is an electron gun is a cathode (negatively charged) encapsulated by a metal cylinder that is called the Control grid. A heating element inside the cathode causes the cathode to be heated up as current is passed. As a result, electrons ‘boil-off’ from the hot cathode surface. These electrons are accelerated towards the CRT screen by a high positive voltage applied near the screen that is called Anode.