Computer Input Device: Keyboard

The keyboard is the oldest and most familiar of all input devices. Keyboards are intelligent devices and contain their own chips. Basically each key acts as a switch which closes when the key is pressed. The microprocessor scans the keyboard hundreds of times a second to see if a key has been pressed; if it has, a code that depends on which key has been pressed is sent to the processing unit. There are three types of keyboard: Enhanced or Extended keyboard, Cordless keyboard and Ergonomic keyboard.