The presentation focuses on the Input and Output Devices

1. Input and Output DevicesInput and Output Devices
ByBy
Dr. Pravin H. GhosekarDr. Pravin H. Ghosekar
M.Sc.(C/S), MCM, DBM, M.Phil(IT), M.Phil(Comm), MBA, BJ. Ph.D.M.Sc.(C/S), MCM, DBM, M.Phil(IT), M.Phil(Comm), MBA, BJ. Ph.D.
HOD Computer DepartmentHOD Computer Department
Dhanwate National CollegeDhanwate National College
NagpurNagpur
08/10/201008/10/2010

2. Input Devices
• An input device is an electromechanical
device that accepts data from outside
world and translates them into a form a
computer can interpret.
• The I/O devices that provide a means of
communication between the computer
and the outside world are known as
peripheral devices

3. Keyboard
• Keyboard is a primary input device.
• It allows input into the computer system by
pressing a set of keys available on a board
connected to the computer system
• The standard keyboard has 101 keys
Keyboard has following keys :
1. Alphanumeric Keys
2. Numeric Keypad
3. Function keys
4. Arrow keys
5. Special keys (Shift,Alt,Ctrl,,Enter, etc)

4. Mouse
• A mouse is a small device that the users can use to point
to a particular place on a screen or to select one or more
icons and execute commands .
• Mouse contains two or three buttons on the top. When
user moves the mouse on the flat surface; the cursor also
moves in the same direction on the screen.
• Some mouse also having scroll wheel on the top of the
mouse which is used to scroll the screen
Mouse are of three different types as follows :
1. Mechanical Mouse
2. Optomechanical mouse
3. Optical mouse
Pointing Devices/ Direct Entry Devices / Point-and-draw
devices :

5. Trackball
• The trackball is a pointing device that is similar to inverted
mouse.
• It consists of a ball fitted in the small external box or on the
keyboard in some portable computers.
Pointing Devices/ Direct Entry Devices / Point-and-draw
devices :
JoyStick
• . It is a vertical stick that moves the graphic cursor
in the direction as the stick moves.
• It consists of a small, vertical lever mounted on a
base that is used to steer (move) the screen cursor
on monitor.
• Joysticks are generally used to control video games,

6. Light Pen
• A light pen is a small pen-shaped device, which contain light sensors
and is activated by pressing the pen against the display screen.
• The sensor is the scanning beam that helps in locating the pen’s
position (X and Y coordinates on the screen).
Pointing Devices/ Direct Entry Devices / Point-and-draw
devices :
Touch Screen
• Touchscreens panels have the ability to display and receive
information on the same screen.
• It is a display which can detect the presence and location of a touch
within the display area.
• Touch screens can sense finger/hand or the stylus (writing utensil
similar to ball point pen) or any other object.
• It enables us to interact with; what is displayed directly on the
screen, rather than indirectly with a mouse or touchpad.

7. Scanner
• Scanning devices are input devices used for direct data
entry from the source document into the computer system.
• Scanners facilitate the capturing of information and
storing it in a graphical format
• It consist of two components, one to illuminate the page so
that the optical image can be captured and the other to
convert the graphical image into a digital format for storing
so that we can process it.
• Scanner are of two types
1. Hand- Held Scanner
2. Flat-bed Scanner
Scanning Devices

8. Optical Character Recognition (OCR)
• OCR is the mechanical or electronic
translation of images of handwritten,
typewritten or printed text into machine-
editable text.
• This device is work similar to the scanner;
it takes inputs from the printed matter or
any other object.
Scanning Devices

9. MICR (Magnetic Ink Character Recognition)
• MICR devices are used by the banking industry to
read the account numbers on cheques directly and
subsequently perform the necessary processing.
Scanning Devices
Magnetic Ink Characters

10. Optical Bar Code reader (OBR)
• A barcode reader (or barcode scanner) is an
electronic device for reading printed barcodes.
• Data coded in the form of small vertical lines
forms the basis of bar coding. Alphanumeric data
is represented using adjacent vertical lines called
Bar codes.
• A barcode reader uses laser beam technology
Scanning Devices

11. Optical Mark reader (OMR)
• OMR is an automatic optical sensing of
marks recorded on a data medium.
• In this method special preprinted forms
are designed with boxes which can be
marked with a dark pencil or ink.
Scanning Devices
This is generally used as
1) Objective type answer papers
2) Market surveys, population surveys etc.
3) Order forms containing a small choice of items.
4) Survey forms which is having objective question
and number of forms.

12. Microphone
Voice Recognition Devices
Vision Input devices / Imaging & Video
Input Devices :
•Web/Digital Camera
Video Camera :

13. Output Devices
• An output device is an electromechanical device
that accepts data from the computer and
translates into a form that can be understood
by the outside world.
• Output produced on display units or speech
output that cannot be touched and it is known
as softcopy output while output produced on
paper or material that can be touched, is known
as hardcopy output.

14. Monitor
• Monitor is a primary output device. The monitor also known as
Visual Display Unit (VDU).
• A monitor uses a Cathode Ray Tube (CRT) to display
information.
• CRT is a picture tube of computer.
• CRT contains electron gun, the electron beam (controlled by an
electromagnetic field), and a display screen.
• The screen is coated with phosphor in a grid of dots called
pixels.
• The electron gun emits an electron beam, which is directed
towards the phosphor-coated display by the electromagnetic
field, and this in turn creates the image.
Resolution: Images are formed on a monitor by a series of dots
or pixels (picture elements). Resolution is expressed as a matrix
of these dots or pixels. For eg, many monitors have 1,280 pixels
columns by 1,024 pixel rows for total of 1,310,720 pixels. The
quality of monitor depends upon the number of pixels (monitor’s
resolution).

15. LCD (Liquid Crystal Display)
• It is introduced in watches and clocks in 1970s
like light-emitting diode (LED) and CRT.
• LCDs consume much less power than LED and
CRT. .
• LCD is an electro-optical amplitude modulator
which is thin and flat display device made up of
many numbers of color or monochrome pixels
arrayed in front of a light source or reflector.
• It is also used in battery-powered electronic
devices because it uses very small amounts of
electric power.
• It is expensive than CRT.
• It has limited viewing angle

16. Printers
• Printers are the peripheral device which
produces output on paper.
• The speed of printer is measured in Character
per Second (CPS), Lines per Second (LPS),
Pages per Second (PPS), depending upon the
type of the printer.
• These printers can be classified into
1. Impact printer : DMP, Line Printer
2. non-impact printer : Laser, Inkjet, Thermal

17. Impact Vs Non-Impact Printers
NON-IMPACT PRINTERS IMPACT PRINTERS
1. Produce better quality print than
impact printers
2. Non-impact printers are quieter i.e.
noiseless
3. The characters and images are
printed without any direct physical
contact with the paper
4. Non-impact printers are usually
more expensive than impact
printers.
5. Non-Impact Printers are faster than
Impact Printers (because they have
fewer moving parts).
6. Speed of Non-Impact printer is
generally measured in Pages Per
Minutes (PPM)
7. Examples : Laser Printer, Inkjet
Printer, Thermal Printer, etc
1. Produce worst quality print than non-
impact printers
2. Non-impact printers generate noise
(because of the hitting activity).
3. The characters and images are
printed by making physical contact
with paper. (in Dot matrix printer
hammer is strike on paper along with
carbon ribbon to print)
4. Impact printers are Cheaper than
non-impact printers.
5. Impact Printers are slower than non-
impact Printers.
6. Speed of Impact printer is generally
measured in Character per seconds
(CPS) or Line Per Minutes (LPM)
7. Examples : Dot Matrix Printer, Daisy
Wheel Printer, etc

18. Dot Matrix Printers
• DMP uses a print head consisting of a series of small pins
to strike a ribbon coated with ink, causing the ink to
transfer to the paper at the point of impact.
• Characters produced are in a matrix format (set of dots)
dotted form.
• The shape of each character, i.e. the dot pattern, is
depends upon number of pins present on head.
• DMP can have 7 / 9 / 18 or 24 pins on print head.
• Dot matrix printers can either be character-based or
line-based.
• It is cheapest, robust printer and low quality printer.
• Its printing speed is 30–1000 cps (characters-per-
second).

19. Laser Printers
• Laser printer uses dry ink (toner), static electricity,
& heat to place and bond the ink onto the paper.
• They use a combination of laser and photocopier
technology.
• Produce image using laser beam on the photosensitive
surface of a drum. The paper rolls by the drum, the toner
is transferred to the paper and fixed into a permanent
image.
• To make the printing permanent; the heat and pressure
is applied on the paper by passing it through a hot roller.
• Laser printers are capable of converting computer
output into print, page by page.
• Laser is high quality, high speed, high volume printer that
work on plain paper or pre-printer stationary. It is
faster, noiseless, expensive but cost effective printer.
• Speed ranges from 10 pages per minute to about 200ppm

20. Inkjet Printers
• Inkjet printer uses a series of nozzles to spray
drops of ink directly on the paper.
• The print head consists of a number of tiny
nozzles to spray ink on paper by making
electrical field on paper.
• Inkjet printers are slower than dot-matrix
printers (40-300 cps), cheaper to buy but are
more expensive in running costs (printing cost is
higher).
• Typical inkjet printers produce 17 to 19 pages
per minute of b/w output and 13 to 15 pages of
color output.

21. Thermal Printers
• A thermal printer produces a printed image by selectively
heating coated thermochromic paper, or thermal paper
(heat sensitive paper) , when the paper passes over the
thermal print head.
• The coating turns black in the areas where it is heated,
producing an image.
• Thermal printer can also print in two different colour i.e.
in black and an additional color (often red), by applying
heat at two different temperatures.
• Thermal printers print faster and more quietly than dot
matrix printers.
• It can produce high quality output in B/W or in colour.
• It is economical printing solution as it require only paper
(no need of ribbon or ink or toner, etc). Thermal printers
are used in ATM, Kiosk, Shopping Malls, Petrol Pump,
Hotels, etc.

22. Plottors
• Plotters are used to produce graphical output
on paper.
• It can print charts, drawings, graphics, maps
etc.
• It is much similar to printer but it is designed
to print graphs instead of alphanumeric
characters.
• Plotters are available in any size to generate
bigger output.
• Plotters are of two types: pen plotter and
electrostatic plotter. Pen plotters have an ink
pen attached to draw the images, electrostatic
plotters work similar to a laser printer.

23. Voice Response Systems
• Voice response systems enable the computer to talk
to its users.
• It consists of an audio-response device that
produces the audio output.
• To facilitate voice response computer must have a
sound card attached/inbuilt into the computer
system. Sound cards having digital-to-analog
converter, that converts recorded or generated
digital data into an analog format.
• Audio-output devices
• Voice Reproduction System
• Speech Synthesizer

24. ThanksThanks