A peripheral is hardware that allows a computer to perform an additional function, but is not something the computer needs in order to work. Main functions of a PC are input processing, output, and storage.
· Input: We enter data with a keyboard, a webcam, etc.
· Processing: The data is manipulated according to program instructions.
· Storage: We keep data and programs in memory systems where they are available for processing.
There are many input and output devices such as printers and computer-based navigation systems.
Output devices are pieces of computer hardware that allow a computer system to communicate information to a user or another system. This information can be in any form, and includes sound, images, and even tactile experiences. Output devices can usually only be used to send data from the computer; items called input devices allow users and other systems to send data to the computer.
Some of the most common output devices allow computers to present information visually. The visual display unit called a monitor that can be found connected to almost every personal computer is the best example of this. Text, pictures, and other images are displayed on the monitor, allowing users to interact with computer programs and receive data. Information shown on a display device is called soft copy because the information exists electronically and is displayed for a temporary period of time. The monitor is our way of knowing whether the computer has understood our commands or not.
Video projectors are another type of output device. They function in a way similar to monitors, but display images over a much larger area.
Printers are one of the most used peripherals on computers. A printer is an external hardware device responsible for taking computer data and generating a hard copy of that data. Printers are commonly used to print texts, images, and photos.
Audio output devices are also common. Computer speakers are the primary source of this form of output. They allow the computer to emit sounds that include music, audio tracks to digitized television shows, and even the voices of other users. Headphones also do the same thing, but are placed closer to the ears so that the sounds cannot be heard by others.
Rarely, output devices can also be input devices. A storage device such as a CD-RW drive is an excellent example of this. The computer uses it as an output device when it is writing information to a CD-ROM or other media that can be read by other computers. However, the computer uses it as an input device when reading information from a CD-ROM or other piece of storage media that has data written on it from another system.
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