ICT

Input Devices

            Input devices enable data to be fed the computer in a from that the computer can use.Input devices are categorized into two types.

            1. Keyboard entry devices

            2. Direct entry devices

A device through which data can be entered to the computer by pressing keys is called a keyboard entry device whereas all the other types of input devices are called direct entry devices.

Keyboard

           The keyboard is the most commonly used input device and has been used since computers were first introduced.They are intelligent devices and contain their own chips.Each key is a switch,which closes when that particular key is pressed.The microprocessor scan the keyboard hundreds of times a second to see if a key has been pressed; if it has,a code that corresponds to that key is sent to the Processing Unit.The CPU then translates this code into the ASCII code (the code that computers use to represent charaters on the computer keyboard), which is the used by the computer program.

Mouse

             Mouse movements on the desktop are translated into digital information,which in turn is fed to the computer,causing the cursor to move on the screen.Underneath the mouse there is a ball which rotates when the mouse is moved by the user and sensors pick up this movement.A mouse usually has two or three buttons,and these are used to make selections on the screen.

                                                   

Microphone

             A microphone can be used to record sound into a computer.Microphones are also used for voice communication through a computer.

Camera

                   Digital cameras store the images digitally rather than on film.Digital still cameras can be connected to a computer and the pictures taken on them can be transferred while digital motion cameras or web cams can be used to create video and for video conferencing purposes.

                             

Scanner

                 Scanner are input devices normally used to scan pictures.The scans are then stored in a computer’s memory where they can then be accessed and modified using a desktop publishing package,befor being printed.Both black and white,and colour scanners are available.