Introduction to CPU
1. Processor 2. Motherboard
3. Ram 4. Hard disk
5. AGP Card 6. Sound Card
7. CD/DVD Rom 8. Casing
9. Power Supply 10. Floppy disk. Others.
Keybord
A keyboard is a computer hardware input device. Originally based upon the design of the mechanical typewriter, keyboards have evolved with technological advances much as other computer has evolved. New ergonomic keyboards can cost as much as a central processing unit or quality computer monitor. Besides the mouse, the keyboard is often the principal input device on home and office computers. Although primarily used for text input, keyboards are also used for precise image and interface manipulation, sending special commands to the and even controlling characters and objects in computer games. Some keyboards include other input/output features such as card readers,
ports, or integrated trackballs. Although there are pseudo-standards regarding key arrangement, keyboard manufacturers are free to create original arrangements and designs. While most keyboards intended for use in English-language environments use the
layout, many keyboards are available with alternative layouts such as Dvorak. Some specialty keyboards have two or more layouts or languages printed on the keys, while others have no layout printed at all. These blank keyboards are intended for touch-typists only, who have no need to look at the keyboard while entering information.
Most conventional keyboards are built using dome-membrane technology. In these models, keys are mounted on a tray which affords them up and down movement only. The keys are supported in the up position by rubber membrane domes on which they rest. The domes are easily collapsible, and quickly return to their upright positions when released from the collapsing force. The underside of each dome houses a graphite bullet, which completes an open circuit underneath the dome when the dome is collapsed. Special circuitry senses the completed circuit, and translates this to a keypress which is then transmitted to the computer. Complex circuitry grids and patterns allow most keyboards to support over one hundred different keys with only about two dozen different circuits. In fact, careful layout of specific meta keys allows two- and even three- key-press combinations to be registered. More complex key-press combinations require very specialized circuitry, which few keyboards today support.
The Desktop
The Desktop offers many features that make using your computer easier. You can easily start programs or applications, copy and move files from one place to another and drag and drop files and program where you want them on the computer or even on to a program's icon to open a file. Open and Save menus are streamlined to allow all applications to have the same basic features plus program specific features.
Operating systems are often backwardly compatible with older system so that older programs will run. Usually when new programs are created they are designed to work with the newest operating system to allow them to use all the newest features.
Mouse
Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to
select objects and text and the right one is used to
access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third button can be used by specific software programs. One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse.
Laptop computers use touch pads, buttons and other devices to control the pointer. Hand helds use a combination of devices to control the pointer, including touch screens.
Monitor
Monitors - The monitor shows information on the screen when you type. This is called outputting information. When the computer needs more information it will display a message on the screen, usually through a dialog box. Monitors come in many types and sizes. The resolution of the monitor determines the sharpness of the screen. The resolution can be adjusted to control the screen's display..
Printers
Printers - The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.
Modem
Modem - A modem is used to translate information transferred through telephone lines, cable, satellite or line-of-sight wireless. City-cell Modem
Scanners
Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner 'scans' the image from the top to the bottom, one line at a time and transfers it to the computer as a series of or You can then take that image and use it in a paint program, send it out as a fax or print it. With optional
Optical Character Recognition (OCR) software you can convert printed documents such as newspaper articles to text that can be used in your word processor. Most scanners use
TWAIN software that makes the scanner accessable by other software applications.
Digital cameras
Digital cameras allow you to take digital photographs. The images are stored on a memory chip or disk that can be transferred to your computer. Some cameras can also capture sound and video.
Sound cards
Sound cards allow computers to produce sound like music and voice. The older sound cards were 8 bit then 16 bit then 32 bit. Though the human ear can't distinguish the fine difference between sounds produced by the more powerful sound card they allow for more complex music and music production.
AGP cards
Colour cards allow computers to produce colour (with a colour monitor of course). The first colour cards were 2 bit which produced 4 colours [CGA]. It was amazing what could be done with those 4 colours. Next came 4 bit allowing for 16 [EGA and VGA ] colours. Then came 16 bit allowing for 1064 colours and then 24 bit which allows for almost 17 million colours and now 32 bit and higher allow monitors to display almost a billion separate colours.
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