Standard Grade

The site I have been using throughout the television section of the course is here.

The shadow mask makes sure that electrons fired from the filament responsible for each colour of sub-pixel do not hit the wrong phosphor dots, e.g. electrons sent by the “green” gun do not reach the phosphor dots that glow red or blue. This animation shows how the shadow mask works.

Remember: electrons do not have a colour.  Colour is only produced when electrons collide with phosphor paint.

What’s inside a colour portable TV?

inside a tv set from mr mackenzie on Vimeo.

Here is a short video clip showing how an image can be built up on a TV screen, one line at a time. In a real TV set, the beam moves much more quickly (about 7000 m/s!) across the screen and 25 complete images are shown each second.

raster scan from mr mackenzie on Vimeo.

Remember that in a real TV set, the beam does not scan its way back up the screen but takes a “flyback” from the bottom right to the top left corner to start on the next image.