Types of Input and Output Devices
                     MODULE 1
Input & Output devices
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Input Devices
• Input is all information put into a computer.
• Input can be supplied from a variety of sources:
– A person
– A storage device on computer
– Another computer
– A peripheral device
– Another piece of equipment, such as a
musical  instrument or thermometer
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Input Devices…
• Input devices gather and translate data into
a  form the computer understands.
• Primary input devices:
– Keyboard - Most common input device; used to type  
in commands and data.
– Mouse or trackball: enhances user’s ability to 
input  commands, manipulate text, images.
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Input Devices…
• Scanners: are peripheral input devices which 
 allow users to import:
– Text
– Graphics
– Images
• Specialized software aids in translating  
information into a format the computer can 
 understand and manipulate.
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Input Devices…
• Digital Cameras: are peripheral input devices 
 that allow users to create pictures and/or  
movies in a digital format.
– Some require specialized software to import 
 images into the computer.
– Some record digital images directly to a disk 
 that can be read by the computer.
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Some input devices
• Mouse
• Keyboard
• Scanner
• Touch pad
• Light pen
• Joysticks
• Microphones
• Digital Cameras
• Touch Screen
• Bar Code Reader
• Trackball
• CD-ROM 44
Output Devices
Used to display processed information 
to the  user either in softcopy or 
hardcopy
Soft copy – output displayed on a 
computer  screen. It is the primary 
output medium.
E.g. Monitor, speaker, LCD 
projector
Hard copy – output produced on 
paper or  micro film.
E.g. Printers, plotters, … 7
Output Devices…
• Monitors: are the most commonly used output 
 device.
• Most monitors use a bitmap display.
– Allows user to resize the display.
– Divides the screen into a matrix of tiny square “dots”  
called pixels.
– The more “dots” a screen can display, the higher the
resolution of the monitor.
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Output Devices…
• Monitors are connected to a computer system  
via a port integrated on the video adapter or  
graphics card.
• Graphics cards convert digital data output from  
software to analog data for display on monitors.
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Output Devices…
Printer
• Most widely used output devices to 
prepare  printed paper documents
• There are Impact and Non-impact 
printers
• Impact printers
Form characters by striking an inked 
ribbon  with hammers against paper
E.g. Dot matrix printers & ink 
printers
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Output Devices…
• Non-impact printers:
Form characters without physical 
contact  between a printer and 
paper
E.g. Laser jet printers
Plotters
capable of drawing complex shapes 
with  multiple colors
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Output Devices…
• VDU
• Flat screen monitors
• Printer
• Plotters
• Speakers
• Headphone
• Projectors
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