The Computer

Operating System

Operating system software controls the overall activity of a computer. Most new computers come with the Windows operating system software.

Input Devices

An input device lets you communicate with a computer. You can use input devices to enter information and issue commands. A keyboard, mouse and joystick are input devices.

Processor

The Central Processing Unit (CPU) is the main chip in a computer. The CPU processes instructions, performs calculations and manages the flow of information through a computer system. The CPU communicates with input, output and storage devices to perform tasks.

Storage

A storage device is used to place information on storage media. The computer uses information stored on the storage media to perform tasks. Popular examples of storage devices include a hard drive, floppy drive, recordable CD-ROM drive, tape drive and DVD-ROM drive.

Output Device

An output device is used to display the results of the information processed by the computer. Common output devices are printers, monitors and speakers.

Software

Software is a set of electronic instructions that tell a computer what to do. You cannot see or touch software, but you can see and touch the packaging the software comes in.

Application software allows you to accomplish specific tasks. Popular application software includes Microsoft® Word and Intuit Quicken.

PC

A PC is a computer designed to meet the needs of a single person and usually refers to IBM-compatible computers. PCs are found in many businesses and are popular for home use.

Power Supply

A power supply changes the alternating current (AC) that comes from an outlet to the direct current (DC) that a computer can use.

The capacity of a power supply is measured in watts. An average computer uses up to 200 watts, whereas an average light bulb uses 60 watts.

Inside a Computer

All computers contain all the same basic parts

Desktop

A desktop case usually sits on a desk, under a monitor.

Ports

Circuit Board

An expansion card is a circuit board that lets you add a new feature to a computer.

An expansion card is also called an expansion board.

Expansion Slots

An expansion slot is used by expansion cards.

Expansion Cards

Some expansion cards are accessible from the back of a computer. These expansion cards contain ports where you can plug in devices. For example, you can plug speakers into a sound card to hear the sound generated by the computer.

Modem

A modem card lets computers exchange information through telephone lines

Sound Card

A sound card lets a computer play and record high-quality sound.

Network

A network interface card lets connected computers share information and equipment