Input Devices

Common input devices are the keyboard, the mouse, the joystick, the trackball and the scanner. Disk drives are input, memory and output devices.

The Keyboard

This is what you use to type information into your computer. It is the most common input device. Keyboards usually have a Qwerty layout.

Different keys on the keyboard have different names. They are used to do different things.

Function keys perform a specific task. This task is set by the program you are using. For example, pressing F1 usually displays the help screen.

Special purpose keys perform special preset tasks. For example, in Word 97 pressing the Print Scrn (Print Screen) key transfers a picture of your screen to the clipboard.

The typewriter keys are used for typing text. They can also be used to perform tasks that appear on the program’s menus. For example, in Word 97, Ctrl+V (hold down the control and the V key at the same time) does the same action as Edit / Paste (select Paste from the Edit menu).

Pressing TAB moves you to the next tab in a word processing program and the next cell in a spreadsheet program.

Caps Lock sets to capitals all the text you write.

The Enter key causes data to be accepted by the computer. If you are typing, pressing the enter key begins a new paragraph.

The cursor control keys move your cursor (the flashing bar where text appears) around the screen.

Numeric keys allow you to enter numbers quickly.

The Mouse

This is another common input device. A mouse is used to point to information on the screen and either Click on it or Click and drag the information.

A Mouse can have one, two or three buttons.

On a two button mouse:

To Click means to quickly press down and release the left mouse button.

To Double Click means to give two clicks very quickly, one after the other.

To Right Click means to click with the right mouse button. This will perform a different action to normal clicking (done with the left mouse button).

To Click and Drag means to point the mouse at an object, hold down the left mouse button, move the mouse, and release the left mouse button. This moves the object you pointed to from where it was to where it is when you release the mouse button.

The Joystick

These are used mainly in computer games. Moving the joystick will move the car / person / object on the screen.

The Trackball

A trackball has been described as an upside down mouse. It is a small ball with buttons around it that is either part of the keyboard or attached to the keyboard. Moving the ball moves the pointer on the computer screen. The buttons are used to do the same things as the buttons on a mouse. A trackball is used instead of a mouse in notebook and laptop computers.

The Scanner

This is used to put both text (writing) and graphics (pictures) into the computer. It digitises the text and images i.e. it converts them into a form that can be used in the computer. This process is known as optical character recognition (O.C.R). Before the text can be used on the computer, it has to be converted into characters by optical recognition software.