Components of computer

Components of computer
Central processing unit (CPU)
A central processing unit (CPU) (formerly also referred to as a central processor unit[1]) is the
hardware within a computer that carries out the instructions of a computer program by performing the
basic arithmetical, logical, and input/output operations of the system.
Two typical components of a CPU are
Arithmetic logic unit (ALU) - Which performs arithmetic and logical operations
Control unit (CU) - Which extracts instructions from memory and decodes and executes them, calling
on the ALU when necessary.
CPU Speed
Megahertz (MHz) - the number of millions of CPU cycles per second
Gigahertz (GHz) - the number of billions of CPU cycles per second

Input and Output devices
The computer will be of no use unless it is able to communicate with the outside world. Input/Output
devices are required for users to communicate with the computer. In simple terms, input devices bring
information INTO the computer and output devices bring information OUT of a computer system.
These input/output devices are also known as peripherals since they surround the CPU and memory
of a computer system.
•Input devices
An input device is any hardware component that allows you to enter data and instructions onto a
computer. Six Widely used input devices are the keyboard, mouse, microphone, scanner, digital
camera and PC video camera.
 Input device captures information and translates it into a form that can be processed and used by
other parts of your computer.
 2.Pointing devices
 3.Game controllers
 7.Digital cameras
 8.Web cams

The keyboard is the most common input device.
Types of keyboards include:
Multimedia and one-touch access

Portable keyboards for PDAs
Pointing Devices
Pointing devices are mainly used to choose and enter commands
Pointing devices tend to have PS/2 connectors or USB connectors
PS/2 connector fits into a PS/2 port, which a small round socket with small holes that fit the pins on
the connector
USB connectors fit into USB ports, and these are small rectangular openings on the back or front of
your computer, or even on your keyboard or monitor
Various pointing devices are available
Types of pointing devices:
1. Mouse
2. Mechanical mouse
3. Optical mouse
4. Wireless mouse
5. Trackball
6. Touchpad
7. Pointing stick

Game Controllers
Game controllers are used mainly to play games

Types of gaming devices

Gaming wheels
Force feed
Other types of input devices include:

Digital cameras
Web cams
Scanner is a light sensitive device that helps you copy or capture images, photos, and artwork that
exist on paper. Types of scanners include:
Stylus is an input device consisting of a thin stick that uses pressure to enter information or to click
and point
Styluses are used with:
Tablet PCs
Graphics tablets

Microphones are used to input audio
Three main types of microphones are:
Desktop microphones
Directional microphones
Digital Cameras

Digital cameras are used to:

Download images to a computer Post pictures to the Web Produce videos
Resolution is measured in megapixels Higher the resolution, better the image quality, but the more expensive the camera

Web cam is a video camera that can be used to take images for uploading to the Web
Output devices
An output device is any hardware component that conveys information to one or more people. Three
commonly used output devices are a printer, a monitor and speakers.
Output devices take information within your computer and present it to you in a form that you can
Main output devices:

Cathode-ray tubes (CRTs)
Flat-panel displays
Liquid crystal display (LCD) monitors
Gas plasma displays
Inkjet – most popular
Makes images by forcing droplets through nozzles
Top speed is 20 pages per minute
Forms images using an electrostatic process
Prints between 3 and 30 pages per minute
Multifunction printer:Scan, copy, fax, and print Can be either inkjet or laser Cost less than buying individual units
                                    Take up less desk space

Speakers:A speaker is a device that produces computer output as sound Speakers are common devices in computer systems Examples include:

Built-in speaker
Two-device set speakers
Surround sound speakers