Peripherals

Output devices

Monitors are an output device and there are two types. One is Cathode Ray Tube (CRT). It works by moving electrons back and forth, when the pass across the screen it lights up and produces an image. The second on is liquid-crystal display. It works having two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causing the crystals to align so that light cannot pass through them.

Printers are also output devices and there are two main types. One is the ink printer. It works by spraying ionised ink onto a sheet of paper and Magnetized plates draw the ink into the desired shape on the paper. The second one is the laser printer and it works by. Another form of output devices is a plotter which is pens that are plotted on to a page and that draw a picture, they are mainly used for technical drawing such as blue prints.

Input devices

An input device is something that feeds data into the computer. One input device is a camera such as a web cam which inputs the image into the computer. The second input is a keyboard is a set of keys which allows the user to enter data into a computer. Another input device is a mouse which is a device which allows the user to control the movement of the pointer on the display screen. The last input device is a scanner which transfers hard copies into electronic data.

Cabling

Coaxial cabling is a wire surrounded by insulation and then a grounded shield of braided wire. They are mostly used for computers.

Optical cabling is a glass wire which reflects the light through the wire which send the signal. Mainly used for television networks.

Twisted pair are two independently insulated wires twisted around one another, it is used to reduce crosstalk and mainly for old telephone networks.