The Physics of Computers

    CRT, or Cathode Ray Tubes were widespread mere years ago, but since then, thinner display technologies have emerged. However, since computers were pairt with CRT monitors for the longest time, we will take a look at the inner working of them. CRT monitors (or televisions) have three vital components to them. First is a source of electrons, a stream of electrons, accelerated from what we usually call an electron gun. Secondly is a way of directing the beam a certain direction. Third is a surface to fire them at.

Image D: A diagram of a cathode ray tube setup.

    Our electrons are fired from the electron gun toward the screen. As the hurtle toward the screen they pass through a set of focusing coils, to focus the electron beam into a finer stream. After that , the electrons than pass through a set of deflection coils. These deflection coils create a magnetic feild that can be varied, in order to steer the electron beam in a certain direction. After being steer in the desired direction, the electrons continue hurtling toward the phosphor covered screen. When the electrons crash into the screen, the charge particles cause the phosphorescent material to glow.

    Laser printers, are another technolgy used with computers that employs some basic ideas of physics to help print documents on a computer. Laser printers, named due to the fact that a laser is used to in part create the image that is printed, employ the basic idea that like charges repel to help create the image to be printed. Laser printers print basically by charging the surface of a photoelectric drum, and then precisely removing charges in certain positions. What is left after this charge removal is a drum that is covered in electric charges (negative), except for where the laser "knocked" the charges off. The drum also comes into contact with a resevoir of toner particles. These toner particles also have a negative electric charge. Since we know that like charges repel, areas of the drum that did not have their charges removed will repel the toner particles, areas of the drum where the charges were removed have a positive charge, which attracts the the toner particles. As a piece of paper than rolls under the drum, these toner particles that are attracted to the drum are then transferred to the sheet of paper, which gives us are printed image.

Image E: A diagram of the photoelectric drum setup of a laser printer.