Input devices are used to convey information to the computer from an outside source. This category of computer device includes a broad range of devices. These devices enable computer users to input text, commands and many types of data to the computer. There are many devices designed to facilitate the transmission of information including pictures, audio and data files.
The mouse is one of the most basic input devices. It is an input device that sends commands to the computer from the user. There are two basic types of mouse: analog and optical. A computer mouse typically features two or more buttons and a wheel. The primary function of the mouse is to control the movement of a movable cursor that—in conjunction with the mouse buttons—allows the user to interact with programs. The cousin to the mouse is the trackball, which is similar to the mouse, except that cursor movement is controlled by manipulating a large ball.
Keyboards come in a variety of configurations, and are primarily used to input text and commands. These commands frequently include the ability to control audio playback and web browsing with specialized buttons. Keyboards also provide several configurations of type placement to enhance usability or typing speed. The most common keyboard layout used in the United States is the QWERTY keyboard. It is named for the six characters used in the top row of letters in order from left to right. The DVORAK-style keyboard uses a type set that is less common, even though it is more efficient.
Microphones are used to capture sounds and transmit them to a sound card. These devices come in a variety of configurations, including stand-alone microphones, web cams, headsets and internally mounted mics. Internally mounted mics are common in laptops where compact function and portability is a factor. Mics found in headsets are bundled with headphones to provide hands-free audio input and output. Microphones built into web-cams provide users with both audio and video input.
Scanners are used to provide computer users with the ability to create digital images of physical objects. Most scanners are designed to work with objects made of paper. Scanners are highly effective for creating digital images of books, photographs and printed or written pages. These devices are frequently coupled with fax machines and printers to provide users with the ability to duplicate documents and fax them or print copies of them.