Russell's Teapot issue 4

Laser printers are another computer technology that uses certain basic physics principles to
assist print documents on a computer. Laser printers, so named because a laser is used to help
generate the picture to be printed in part, utilise the basic principle of similar charges repelling
to help create the image to be printed. Laser printers work by charging a photoelectric drum’s
surface and then accurately removing charges in certain locations. Except for where the laser
“knocks” the charges off, what is left after this charge removal is a drum coated in electric
charges which is negative. A reservoir of toner particles also comes into touch with the drum.
A negative electric charge is also present in these toner particles. Because like charges repel,
sections of the drum that have not had their charges removed will repel the toner particles, but
areas of the drum that have had their charges removed will have a positive charge, which will
attract the toner particles. These toner particles that are attracted to the drum are subsequently
transferred to the sheet of paper as the paper rolls beneath the drum, giving us a printed image.
The hard drive is one of the most widely used storage devices for computers today. Because all
computer data can be converted to binary, which is merely a sequence of ones and zeros, storing
this data requires only a medium with at least two states. Magnetic media are one of the
cheapest options, and because the North and South poles of a magnet parallel the two states of
a binary bit, one or zero, they are a sensible choice. We can make the magnet represent a zero
bit or a one bit by changing the magnetic direction of the material. Similarly, we may use a sensor
to determine which pole is closest to the read device and then interpret that information
back into words.
By Jaishan Jethwa