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Components of Computer
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Input
Any thing given tothe computer isknown as input
such as instructionsor data
Converts raw datainto electronic form
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Input Devices: Giving Commands
Input devices are types of hardware that enable you
to get programs, data, commands, and responses
into the computers memory
Keyboard
Mouse
Stylus
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Keyboard
Traditional Looks like typewriter with
extra keys
Non-traditional
It is used for specific purpose
Fast food restaurants
Each key represents a food
item rather than a character
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Keyboard
Main Keyboard
Typewriter keys
Special command keys
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Keyboard
Numeric Keys Num Lock toggle On n umeric data & math
symbols
Off cursor movement Cursor Movement Keys
Function Keys F1-F12
Give commands
Software specific
F1 is the help key in most programs.
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Keyboard
Special Keys
Enter
Esc
Alt
CtrlCaps Lock
Shortcut
Windows
Shift
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Shift:
Output a capital letter or symbol when pressed along withan alphanumeric key.
Select text for editing when pressed along with cursor
movement keys.
Ctrl:Produces different results depending on the program youare using.
Ctrl key combinations provide shortcuts for menu
commands.
Alt:Produces different set of results
In windows, Alt key combinations enable you to navigate
menus and dialog boxes without using mouse.
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Enhanced / Extended
Keyboard
Types of Keyboard
Enhanced orExtended keyboard Typically 101 keys
laid out in the QWERTY fashion; connected to the
computer by a serial cable Cordless keyboard Uses infrared or radio wave
signals
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Ergonomic Keyboard
Types of Keyboard
Ergonomic keyboard
Designed to help prevent damage to nerve tissues in the
wrist and hand due to repeated motion. It enables the users hands to remain positioned
correctly while reducing bending and strain
Designed for people who type for extended period and
suffer from wrist and hand fatigue.
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Pointing Devices
A mouse is a small, lightweight input device.
It is also called pointing device
Position a pointer / cursor on the screen Controls drawing instruments in graphics
applications
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Pointing Devices
Mouse
Types
Mechanical Optical
Wireless
Features
Palm-sized 1 or 2 buttons
Wheel
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Mechanical
1. Contain a small rubber ball.
2. Ball rolls inside the case when you move the mouse ona flat surface.
3. Rollers and sensors send signals to the computer,
telling distance, direction and speed of ball.
Optical
1. Emits a beam of light from its underside.
2. Uses the lights reflection to judge the distance,
direction and speed of its travel.
Wireless
1. Give computer users cordless accessibility to their mice
and to interact with their computer.
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PS/2 Port
The color-coded PS/2 connection ports:
Purple for keyboard
Green for mouse
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Other Types ofPointing Devices
Joystick
Touch Pad
Touch
Screen
Trackball
PointingStick
Pen
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Other Pointing Devices
Trackball Upside-down mouse
Ball on top
Roll ball with hand Requires less space than
mouse
Laptop computers
Touchpad Pressure-sensitive pad Cursor moves as you slide
your finger
Laptop computers
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Other Pointing Devices
Joystick
Short lever Handgrip Distance and speed of movement control pointer
position
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Touch Screens
Human points to a selection on the screen
Touch Screen is a video display screen that
receives input from touch of finger.
Types
Senses finger pressure
Light pen for pointing
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Touch Screens
Self-help stations
Easy to use
Where found Malls Government offices
ATM Fast food restaurants Drug stores
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Pen-based Computing
Small hand-held devices
Electronic pen (stylus) Pointer
Handwritten input
Personal Digital
Assistants (PDA)
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Optical Scanners
Optical recognition
Light beam scans input data
Most common type of source input
Document imaging converts paper documents to
electronic form
Converts scanned picture into characters OCR
Exact computer-produced replica of original
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Types of Scanners
Flatbed One sheet at a time
Scans bound documents Sheetfeed
Motorized rollers
Sheet moves across
scanning head Small, convenient size
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Types of Scanners
Handheld
Least expensive
Least accurate
Portable
Wide document causes problems
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Read barcodes which are patterns of printed barsappear on product packaging.
Barcodes identify product and provide informationabout product such a price.
BCR emits a beam of light that is reflected by the barcode image.
Light sensitive detector identifies barcode image byrecognizing bars.
BCR converts printed bars into a code the computercan understand.
Reader then feeds the data into the computer.
Bar Code Readers
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Voice Input
Speech Recognition Translating voice to text is a capability
known as speech recognition.
Speech recognition devices Input via a microphone
Voice converted to binary code
Problems Speaker-dependent Voice training
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Voice Input
Discrete work systems Understand isolated words
Pause between words Difficult for dictation
Continuous work systems Normal speaking pattern
Easy to use
Faster and easier to dictate
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Digital Cameras
Photos stored in electronic form
No film
Point and shoot
Edit
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Webcam A digital camera designed to
take digital photographs andtransmit them over the internet.
(WEB CAMERA) A video camerathat attaches to a computer typically via USB or that is builtinto a laptop or desktop screen.It is used mostly for videophoning over networks such as
Skype as well as tocontinuously monitor an activityand deliver the video to a Webserver for public or privateviewing.
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