Chapter 2 HAEDWAER

COMPONENTS OF A COMPUTER There are mainly 2 types of COMPUTER COMPONENTS :- 1-Hardware. 2-Software.

Question What is the difference between a calculator and * a computer? The definitional difference between the two is that a computer can be reprogrammed to perform a multitude of different tasks whereas a calculator is engineered only for one specific set of tasks.

Hardware Hardware: The hardware consists of all devices of the Computer that you can see and touch. Hardware types are: 1) Input Devices i.e. the keyboard and mouse . 2) Output Devices i.e. monitor and printer 3) Processing Devices or CPU. 4) Storage Devices i.e. memory , hard disk and flash memory 5) Others Devices i.e. modems and cards.

Hardware

1- Input Devices - Input devices : are hardware used to translate words, sounds, images, and actions that people understand into a form that the computer can understand . Inputs is referred to Soft Copy

Examples of Input Devices 1-Keyboards 2-Pointing devices (Mouse). 3-Scanning devices 4- Microphone.

Keyboard - Keyboards: It is used to type data into the computer or input data. - Keyboards come in a variety of designs. - The most common types are: 1-Traditional keyboards. .2-Flexible keyboards 3-Wireless keyboards … etc

Keyboard Entry

Keyboard Entry 1) Numeric keypad : used to enter numbers and arithmetic symbols. 2) Function keys : provides shortcuts to specific tasks. 3) Escape key : cancels a selection or a procedure. 4) Windows key : displays the start menu. 5) Space bar : enters blank spaces between characters. 6) Navigation keys : controls the cursor or insertion point on the screen.

Pointing Devices - Pointing Devices provide a comfortable interface that creates machine-readable data that can go directly to the CPU. - Examples of Pointing devices : mouse, joystick ,touch screen, light pen …..etc.

Mouse - Mouse : controls a pointer that is displayed on the monitor. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. Similar devices to Mouse : Track ball ,Touch pads

Mouse A mouse incorporates a mouse pointer which usually appears in the shape of an arrow. Some mouse are also equipped with a wheel button that can be rotated to scroll through information.

Other Pointing Devices 1- Joystick Joystick – input for computer games. 2- Touch Screen a kind of monitor with a clear plastic outer layer Easy to use. 3- Light Pen

Scanning Devices Scanners move across text and images . - Scanning devices : convert scanned data into a form the system unit can process. - Examples of scanning device : Flatbed Scanner, bar code reader.

Image Capturing Devices 1) Digital cameras - Images recorded digitally on a disk 2) Digital video camera - Records motion digitally 3) WebCams - Broadcast images & videos over the Internet Imaging capturing devices create or capture original images

2- Output devices - Output devices : are any hardware used to provide or to create output. - They translate information that has been processed by the system unit into a form that humans can understand.

Output devices - The most widely used output devices are : 1- monitors. 2- printer. 3- speakers and headphones.

Monitors - Known as screens or display screens - A monitor takes information and display the screen for you to look at.

Monitors Standards indicate screen quality (resolution). Some monitors are used on the desktop, others are portable. Features – most important is clarity. Resolution – one of the most important features; images are formed on a monitor by a series of dots or pixels (picture elements). Dot (pixel) pitch– the distance between each pixel; most newer monitors have a dot pitch of 31 mm (31/100th of a millimeter) or less. Refresh rate – indicates how often a displayed image is updated or redrawn on the monitor; most monitors operate at a rate of 75 hertz which means that the monitor is redrawn 75 times each second; flickering indicates that the monitor rates are lower than 75 hertz. Size – or viewable size is measured by the diagonal length of a monitor’s viewing area. Common sizes are 15, 17, 19, and 21 inches.

Types of Monitors 1- Cathode-ray tube (CRT) monitors 2- Flat-panel monitors or Liquid Crystal Display (LCD)

Printers Printer : Translates information that has been processed by the system unit and present the information on paper Output referred to as hard copy.

Printers Printers translate information that has been processed by the system unit and present the information on paper. Output is called hard copy. Features: Resolution – measures the clarity of images produced, measured in dots-per-inch (dpi). Most printers use an average of 1200 dpi; the higher the dpi, the better the quality of image produced Color capability – more expensive to print in color; usually have the option to print in either color or b/w. Speed – measured in the number of pages printed per minute, 15-19 pages per minute is the average for a single color page (black); 13-15 pages per minute for color. Memory – used to store printing instructions and documents waiting to be printed.

Types of Printers : 1- Ink-jet printer 2- Laser printer 3- Thermal printer

speakers and headphones translate audio information from the computer into sounds that people can understand .

Combination input and output devices *Fax machines *USB Drives.

Compare between the three Printers : Assignment Compare between the three Printers : 1- Ink-jet printer 2- Laser printer 3- Thermal printer