2. Input and Output devices

Monitor

A component you connect to your computer, which displays a user interface.

Tablet PC

A laptop computer with a sensitive touch screen that can be used instead of the keyboard.

Inkjet Printers

A non-impact printer (usually strikes through an inked ribbon, making marks on the paper), uses tiny dots of ink sprayed onto the paper, forming the shapes of characters and pictures. Quiet, produce good quality output. Usually colour prints, popular for home and small-office use.

Webcam

A type of digital video camera where the image captured is viewed using a computer.

dot matrix printer

A type of printer that uses a matrix of pins striking paper through an ink ribbon to create dots on the paper, forming alphanumeric characters and graphic images. (12)

Speaker

An output device which emits sound.

Keyboard

Has keys for alphabetic characters and numbers. (abaosdihdsljsqnewfivbo) There are extra keys for special functions ( .][-=\/';?>!@#$%*^).

Liquid Crystal Monitors

LCD monitors. They allow the screens to be FLAT, instead of bulky as with CRT (see previous). They consume less power than CRT displays.

Fan

Like regular fans, to keep an air flow inside the motherboard to avoid it from overheating.

Cathode Ray Tube Monitors

Monitors used to be the commonest type of monitor. CRT monitors can be relatively bulky

Printers

Printed output is often called a printout or hard copy. Two types: Impact printer and Non-impact printer.

Scanner

Reads printed data into the computer. Types of scanner: - hand-held scanner - flatbed scanner - sheet-fed scanner

Laptop

Slightly larger and much heavier than an A4 file.

Digital Cameras

Store pictures on a memory card (in a format that can be read, saved and displayed on a computer). Pictures can be transferred and edited using graphics software on the computer.

Joystick

This is a lever which gives the user similar control to a mouse, but they are usually built into game consoles.

Touch Screen

This is a type of screen which is sensitive to touch. Instead of using a mouse you can touch the screen to control the cursor

Tracker Ball

This is another alternative to a mouse. It looks like a mouse, but instead of moving the mouse you move a ball to control to cursor.

Output device

used to display the information which the input devices send into the computer. Examples are monitors, speakers and printers.

Monitors

"Visual display units (VDUs). Come in different styles and quality levels. Adv. of Monitor screens: - Enables the use of a graphical user interface. - Interactive, on-screen use of a computer is more natural and intuitive than programming. Disadv. of Monitor screens: - Screen size can limit the extent and detail of what can be seen. Eg.: it is possible to refer to several printed pages at the same time. - Screen displays can be difficult to read for people who have impaired sight.

Graphics Tablet

Flat rectangular pad between 6-30 inches (15 and 76 cm) wide. It works with a stylus (a hard point), which you can draw/write on the surface to produce drawings in the computer. There are several types of stylus: pen-shaped, or a puck (small rounded device with cross-hairs for tracing lines accurately and with a number of buttons). Mainly used for computer-aided design and drawing.

Headphones

Two small speakers built into a headset.

Trackpad

Used instead of a mouse to move the pointer on the display. It is commonly found on laptops, and is sensitive to touch.

Sensors

Used to input data about the environment into a computer. Eg.: Sensors to record light intensity Adv. of sensors: - Can be placed in dangerous locations where people would be hurt. - Can continuously and reliably record data whereas to organise this using people could be much more unreliable and expensive. - Can record data that people do not sense or do not sense accurately, such as humidity. - The data recorded by sensors can be automaticaly recorded in a form that can be processed by a computer. - Data can be collected by a sentral computer from sensors in remote locations. Saves time, data can be collected more frequently. Disadv. sensors: - Cannot interpret the data - Detect a very restricted range of the different types of data.

Mouse

a hand-operated electronic device that controls the coordinates of a cursor on your computer screen as you move it around on a pad. It is an input device.

Laser Printers

a non impact printer (see previous) that use laser light to make patterns of ink on a drum. this drum then transfers the ink to the paper, and finally a heating process fuses the ink to the paper. Excellent quality, quick. Expensive (>inkjet printers) often black and white.

Input device

used to enter information into the computer. Examples are keyboard, joystick, modem, mouse, scanner, voice recognition, touch screen, microphone, light pen, and stylus .