Modern personal computers usually have a set of peripherals at the order.
Peripherals are any additional and auxiliary devices which are connected to the personal computer for expansion of its functionality.
Let's consider some of peripherals.
The printer (print - to print) – the device for printing of text and graphic information. Printers, as a rule, work with A4 or A3 format paper. Laser and jet printers are most widespread today, matrix printers already went out of use.
In matrix printers the printing head consisted of a number of thin metal needles which at movement along a line at the right time struck through a painting tape and by that provided formation of symbols and the image. Matrix printers possessed the low speed and quality of the press.
In jet printers paint under pressure jumps out of openings (snuffled) in a printing head and then sticks to paper. Thus formation of the image comes as though from separate points - "blots". For jet printers the high cost of expendables is characteristic.
In laser printers a laser beam, running on a drum, electrifies it, and the electrified drum attracts particles of a dry ink then the image is transferred from a drum to paper. Further the sheet of paper passes through the thermal reel and under the influence of heat paint is fixed on paper. Laser printers possess the high speed and quality of the press.
The plotter (graph plotter) – the device for a conclusion to paper of big drawings, drawings and other graphic information. The plotter can bring graphic information to A2 format paper more. Structurally in it it can be used or a drum of rolled paper, or a horizontal tablet.
The scanner (scanner) – the device, allowing to enter graphic information into the computer. The scanner at movement on the picture (the text leaf, the photo, drawing) will transform the image to a numerical format and displays it on the screen. Then this information can be processed by means of the computer.
The manipulator a mouse (mouse) – the device facilitating input of information in the computer.
The CD ROM disk drive – the device for reading information which has been written down on laser compact disks (CD ROM – Compact Disk Read Only Memory that in transfer means a compact disk with memory only for reading). On compact disks it is possible to store a large number of information (to 650 Mb). Such disks are used for storage of reference information, big encyclopedias, databases, music, a video information, etc.
The main indicator for the CD ROM disk drive is a speed of reading of information from a compact disk.
The DVD disk drive is further development of laser technologies. In it the advanced technology of use of a laser beam is applied to record and reading information from compact disks. The abbreviation of DVD means Digital Video Disk (the digital video disk) or in other treatment - Digital Versatile Disk (a digital multi-purpose disk).
Unlike the disks CD ROM the disks DVD can use both surfaces for work. And the technology allows to write down two layers of data on each of the parties.