CRT Basics 

A CRT projector works on the same principles as your home TV does, with a few differences. Most video projectors do not have a TV tuner built in, so you need a VCR or satellite dish as your channel selector and tuner.

The sound is routed through your home stereo or surround sound system rather than through the speakers built into the projector.

The video image is formed on three picture tubes, each of which produces one of the primary optical colors. High voltage within the set is required to excite the electron beam within the picture tube, which then generates light output when the electron beam hits the phosphor surface of the tube. The red, blue and green images are then aligned (or ‘converged’) on the screen to form one color integrated image.

The main components of the video projector are the picture tubes. These are three tubes that produce a high amount of light on the phosphor surface which is then projected through lenses onto the screen. Myths surround these picture tubes too.
In the next sections I will outline the basic truths.