Vacuum Tubes at Home
The vacuum tube that hundred years ago only had a role in scientists' exploration of the processes in matter, has, thanks to many technical inventions, evolved into an apparatus that is found in virtually every home and office – the television tube and the computer screen.
They work similarly to Thomson's discharge tube - an electron beam is accelerated and deflected and hits the end of the glass tube, giving rise to a visible spot. By deflecting the electron beam very quickly and modulating it to produce weaker or brighter spots, a complete image can be constructed with an electron beam. By making it hit small spots on the glass that emit either red, green and blue light, complete color images can be produced. In most television sets and computer monitors there is a modern electric discharge tube consisting of an electron accelerator in an evacuated glass tube.