2. INPUT DEVICE :-
An input device is a piece of computer hardware
equipment used to provide data and control signals to
an information processing system such as computer
or information appliance.
3. Major input devices :-
Some of the major input devices are:-
KEYBOARD
MOUSE
JOYSTICK
OMR( OPTICAL MARK READER)
LIGHT PEN
POINT OF SCALE TERMINAL(POS TERMINAL)
BCR( BAR CODE READER)
OCR (OPTICAL CHARACTER READER)
MICR( MAGNETIC INK CHARACTER READER)
4. Keyboard is a flat piece of plastic board many
buttons arranged on it . These buttons are called
keys. The keyboard help in inputting the data to the
computer . There are following functions keys on a
keyboard like F1 to F12 , numeric keys 0 to 9 and
alphabet keys A to Z . It consists caps lock key, num
lock key ,shift key ,back space key ,space bar key
and enter key etc.
Standard keys on a keyboard is 101.
KEYBOARD:-
5. MOUSE :-
Mouse is a pointing device it consist three buttons. Left
button right button and scroll button . Left button is used to
select an object , right button is used to excess the properties
of an object and scroll button is used to scrolling the page up
and down.
Mouse are basically used in desktop computer system when
placed on a fixed space than we use mouse.
6. JOYSTICK:-
Joystick is a pointing device most common used to
play animated games on a micro computer. Joystick
works on the same principal as a trackball. Joysticks
are often used to control video games and usually have
one or more push buttons whose state can also be read
by the computer.
7. OPTICAL MARK READER:-
Optical mark reader is a special optical scanner device which
can be used to recognise the type of mark made by pencil or
pen. This device is used as academic and examination centres
to grade aptitude test. Where candidate mark the correct
answers on a special sheet of paper having multiple circles.
These answer sheets are the directly read by the optical mark
reader and the corresponding information is sent to a CPU for
processing.
8. LIGHT PEN:
Light pen is a pointing device that can be a used to choose a
displayed menu option or to draw picture on the screen. It
consist of a photocell and an optical system placed in a small
tube as the user moves tip on the pen over the surface. It is
able to detect the light coming from a limited field of view. A
light pen is also useful for graphic , the user at computer
added design terminal can draw directly on the screen with
the pen.
9. POINT OF SCALE TERMINAL (POS TERMINAL ):-
It is a higher version of the bar code reader , also used in
departmental stores. In this case, the salesman move about,
carrying with them a barcode reader and a laptop computer.
When a customer wants to purchase something, the salesman
with the aid of the barcode reader and the laptop computer,
decodes the detailed information in printed on the barcode of
that product.
10. BCR (BAR CODE READER):-
Various commodities available in the market have a sequence of
black and white lines of varying thickness, closely placed
together printed on the cover . These lines which are known as
barcodes . Barcodes contains the various information about
the product, e.g. name of the product, manufacturing date,
producer name, expiry date, cost of production etc.
11. OCR(OPTICAL CHARACTER READER):-
Optical character reader is a optical scanner used to scan
documents place under them by examining each character
present in the document and matching it the character may be
either typed or hand return. In case of hand return characters
special care has to be taken to ensure that the characters are of
standard size , line making up the character are connected.
OCR devices are particularly used for large volume
application such as reading zip codes in postal service and
printing bill of credit card.
12. MICR(MAGNETIC INK CHARACTER READER:-
It is popularly used in banks for verifying important
documents like drafts, cheques etc. At the bottom side of such
documents, a set of symbols are printed with magnetized ink.
13. OUTPUT DEVICES:-
An output device is any device used to send data from a
computer to another device or user . Most computer data
output that is meant for humans is in the form of audio or
video. They perform the following function:-
Receive result from memory
Convert data into human readable form
Display result to the user
14. DIFFERENT TYPES OF OUTPUT DEVICE:-
MONITOR
PRINTER
IMPACT PRINTER
NON –IMPACT PRINTER
SPEAKER AND HEADSETS
PLOTTER
MULTIMEDIA PROJECTER
15. MONITOR:-
The monitor is the most common and the most important
output device. It is also called a visual display unit. The
output viewed on a monitor is called a soft copy. The monitor
is a visual display device to present output information in the
form of text, graphic, or video on the monitor screen.
16. PRINTERS:-
Printers are used to produce hard copy output. They print
processing results on paper. Printers are divided into two
main categories:-
Impact printer
Non- impact printer
17. IMPACT PRINTERS:-
The printer that print the character by striking against the
ribbon and into the paper is called impact printer. There are
two types of impact printer.
Character printer
line printer
18. CHARACTER PRINTER :-
These printer print one character at a time is called
character printer . For example Dot matrix printer.
They form character and all kind of image as pattern
or dots.
19. LINE PRINTER:-
These printer print one line at a time. So it is called as line
printer. These printer use impact technology. There is
mechanical contact between head and a paper . These are first
printer having speed in the range of 3000 lines per minutes.
20. NON – IMPACT PRINTERS:-
Non impact printer that prints the character without striking
against the ribbon and on the paper is called non impact
printer. These printer print a complete page at a time so also
called page printer . There are two types of non impact printer.
Inkjet printer
laser printer
21. INKJET PRINTER:-
These printer prints the
character by spraying the
paper with electrically
charged ink . They give
better quality than
character printer. They are
cheaper than laser printer.
LASER PRINTER:-
These are based on laser
technology with high speed
and high quality printing .In
these printer a laser beam is
used to write the image on
a paper.
22. SPEAKER AND HEADSETS:-
Speaker and head sets produce sound output. We can listen
recorded voices, sounds or music with the help of speaker or
headset. Speaker produce sound output with the help of
sound card.
23. PLOTTER:-
A plotter is an output device used to produce image quality
graphics in a variety of colors. Plotter are used to print large
maps, architectural drawings, graphs and charts. Plotter are
used o draw different design of building or internal structure
of machines. Plotters offer the fastest way to efficiently
produce very large drawing or color high resolution graphics.
Engineers and architects use plotters.
24. DRUM PLOTTER:-
In drum plotter both paper
and drum move to produce
the output. The plotter was
the first output device to print
graphic and large engineering
drawings.
FLATBED PLOTTER
In this plotter the paper is fixed and drum moves. Flatbed
plotters have a large horizontal surface on which the paper is
placed.
25. MULTIMEDIA PROJECTOR:-
Multimedia projector is used to produce computer output on
a big screen. These are used in meeting rooms or in
classroom of educational institutes. Since the output
produced by multimedia projector is displayed on a large
screen, it can be viewed by a large number of people in a hall,
meeting /conference room or a class room .Mostly teachers
used data projector in class room for delivering lectures.