DEVICES´ DEFINITIONS

Keyboard

A computer keyboard is an input device that enables the user to enter characters (letters, numbers and symbols) into a computer. The keyboard consists of rows of keys with each key representing a different character. There are different types of keyboards available, for example, QWERTY keyboards, ergonomic keyboards, braille keyboards.

Monitor

A monitor is an output device similar to a television screen. It receives signals from the computer and displays that information for the user to view. Types: CRT, TFT, LCD, etc

Mouse

A mouse usually has between 1 to 3 buttons which users 'click' in order to point and select objects on the screen. The data from the mouse is transmitted to the computer.

A mouse is a hand held pointing device that is classed as a manual input device.

Scanner

Scanners, or computer scanners are used to transfer images or text from paper into a digital format that the computer can use. Once the information has been transferred, it can then be edited, printed, or uploaded to the Internet.There are two main types of scanner:

1. Flat-bed scanner
2. Hand-held scanner

Printer

A printer is an output device. Users can print text and pictures on to paper. A printer can also work with digital cameras to print directly without the use of a computer. There are different types of printers.

• Laser printers
• Ink-jet printers
• Impact or Dot-Matrix printers

Headphones

These are an example of an 'output device'. Headphones may be connected to the computer's sound card so you can listen to a sound file.Some headphones also have a microphone attached so you can listen and speak.

Modem

A Modem is a device used to convert digital data to analogue data in order to transmit it over the telephone network (MODulation). It will also convert the analogue data back into digital data when the computer is receiving data from the telephone network (DEModulation).

Compact Disk

A compact disc or "CD" is a flat round disc used to store data. They are used to store music and other sounds (and sometimes called an "audio CD"). A standard CD-ROM can store up to 700 Mbytes of data. As a comparison a DVD can store about 4700 Mbytes of data.

CDs come in different formats:

• CD-ROM - Read Only Memory
• CD-RW - Read Write
• CD-R - Recordable

Barcode Reader

A barcode reader, also called a price or Point of Sale (POS) scanner is a hand held input device used to capture and read information contained in a bar code. They are used in almost all modern retailers, most commonly in supermarkets.

Touch Screen

A touch screen is the only device which can be classed as both an input and an output device. It consists of a display monitor that is able to sense the location of a finger touching the screen.

Hard Disk

A hard disk is a magnetic storage device for digital data. Most personal computers contain an internal hard disk that can store large amounts of data, often hundreds of Gigabytes.

Floppy Disk

Floppy Disk This is a storage medium that can hold about 1.44Mb of data. The floppy disk has been around since the 1980's but only recently has it been largely replaced by 'memory stick technology' which can store vastly more data (1000 times more!)

Graphics Tablet

This is an input device which is often used by graphics designers and illustrators to work with images or hand drawn designs. A graphics tablet has two parts. The first part is a slender slab that lies flat on the table. The second part is a special pen. The tablet can sense how the pen is moving around on its flat surface. By moving the pen around you are able to draw lines and pictures.

Plotter

An output device. Plotters are often used by engineers, designers and architects to produce large technical drawings (often a metre wide and any length).

Tracker Ball

A point and click device similar to a mouse. A palm-sized ball is nested in a cradle and as you roll it around, the mouse pointer moves around on the screen. Popular with CAD applications.

PDA

Short for Personal Digital Assistant. A PDA is a handheld machine that lets you manage a diary, contact list, address book, 'To-Do' lists and other functions. Modern PDAs may also double up as mobile phones, email reader and (limited) internet browsing. A PDA typically consists of an LCD screen, either colour or monochrome, and some input device, such as a touch sensitve pen although some do have tiny keyboards.

Joystick

A joystick is an input device which is mostly used for playing computer games such as flight simulators.

Central Processing Unit (CPU)

A CPU (Central Processing Unit) is the core of every Personal Computer. Without it, no PC can function.

The CPU is a microchip that is installed on a motherboard and acts as the computer’s brain - performing calculations and coordinating the hardware components.

DVD

DVD is an acronym. It is a short way of saying "digital video disc" or "digital versatile disc".

DVDs can store 4.7 Gigabytes of information, while a Compact Disk can only hold 700 Megabytes.