4. KEYBOARD
A computer keyboard is one of the
primary input devices used with a
computer that looks similar to those found
on electric typewriters, but with some
additional keys. Keyboards allow you to
input letters, numbers, and
other symbols.
The keyboard has five sections 1) Typing
keys 2) Numeric Keys 3)Functional keys
4)Control Keys 5) Special purpose keys
5. Five sections of keyboard
Typing keys (1,2,3……, A,B,C…)
Numeric Keys (Numeric keys on right
side)
Functional keys (F1,F2…. On top side)
Control Keys (Cursor keys,ctrl,alt…)
Special purpose keys(Enter ,Space ,Shift
,Spacebar …)
6. Advantages of keyboards
Disadvantages of
keyboards
Most computers come with a
keyboard supplied
It is easy to make mistakes
when typing in data
People are used to using
keyboards to enter data,
they need very little training
If you can't touch type, it
can be time consuming to
enter data
A skilled typist can enter
data very quickly
Keyboards are not suitable
for creating diagrams
Specialist keyboards are
available e.g. ergonomic,
gaming keyboards
Disabled people often find
keyboards difficult to use
7.
8. MOUSE
A mouse is a hardware input device that
was invented by Douglas
Engelbart in1963 .Mouse is a small
handed device having two or three
buttons on its upper side.
A mouse is classified as physical mouse
and optical mouse.
9. Classifications of mouse
Physical mouse:- It has a rubber on the
bottom side that protrudes when the
mouse is moved . It requires a smooth ,
dust free , such as a mouse pad on which
it is rolled
Optical Mouse:- It uses Light Emitting
Diode(LED) and a sensor to detect the
movement of mouse. Optical mouse was
introduced by Microsoft in 1999.
10. Advantages of mouse Disadvantages of mouse
Ideal for use with desktop
computers
They need a flat space close
to the computer
Usually supplied as part of a
new computer system
Older style mouse which
have roller balls can become
clogged with grease and
grime and lose their
accuracy until cleaned.
Most computer users are
familiar with them and
require little training
Excessive use can lead to
health problems such as
repetitive strain injury
(R.S.I.)
Works well in conjunction
with a keyboard for data
entry
If the battery wears out in a
wireless mouse, it cannot be
used until it has been
replaced
11.
12. JOYSTICK
A joystick is an input device that allows
the user to control a character or machine
in a computer program, such as a plane in
a flight simulator. They look similar to the
control device you would find on an
arcade game, but nearly always include
extra buttons for additional
functionality. Today, most computer
joysticks connect to the computer using a
USB port
13. Advantages of
joysticks
Disadvantages of
joysticks
They give a better
gaming experience for
racing or flying styles of
computer games
Some people find
joysticks more difficult to
control than a traditional
mouse.
Joysticks are not
particularly robust and
can break easily if too
much force is used on
them.
14.
15. Scanner
With hardware, a scanner or optical
scanner is a hardware input device for a
computer. Scanners allow a user to take a
printed picture, drawing, or document and
convert it into a digital file (either
an image or a text file) so that it can
stored, viewed, and edited on a computer.
A scanner can be connected to a
computer using many different interfaces
although today is most commonly
connected to a computer using USB.
Two types of scanner are :- 1) Hand Held
Scanner 2) Flat bed Scanner
16. Types of Scanner
Hand held Scanner:-Handheld scanners
are usually only a few inches wide and are
held in the hand whilst they are rolled
across the document to be scanned. The
images produced are generally not as
large or as high quality as those captured
with a flatbed scanner.
Flat-bed Scanner:- The most popular
type is the flatbed scanner. This is
probably the one that we use at school.
They can scan larger images and are
more accurate than handheld scanners.
17. Advantages of scanners
Disadvantages of
scanners
Flatbed scanners are very
accurate and can produce
reasonably high quality
images.
Images produced by the
scanner can take up a lot of
memory space.
Any image which is digitised
by the scanner can then be
included on electronic
documents.
Images lose some quality in
the scanning and digitising
process.
Images once digitised can be
enhanced with a graphics
application.
The quality of the final image
is dependent on the quality
of the original image .
Can accurately capture an
image, but the original
source may be more
important than the scanned
image.
18.
19. Magnetic-Ink Character
Recognition
Magnetic-Ink Character Recognition,
MICR is a font capable of recognition
using magnetically charged ink.
Computers equipped with the right
hardware and software can print or read
the character printed in such ink. MICR
font is commonly used to print checks,
deposit slips, mortgage coupons, etc.
20. Advantages of MICR
Disadvantages of
MICR
MICR is difficult to forge. MICR readers and encoders are
very expensive.
Documents can still be
read when folded or
written on.
The system can only
accept a few different
character sets.
21.
22. Optical Character Reader
Optical Character Recognition or
Optical Character Reader, OCR is the
process of taking an image of letters or
typed text and converting it into data the
computer understands. A good example is
companies and libraries taking physical
copies of books, magazines, or other old
printed material and using OCR to put
them onto computers.
23. Advantages of OCR Disadvantages of OCR
Cheaper than paying
someone to manually
enter large amounts of
text
Not 100% accurate,
there are likely to be
some mistakes made
during the process
Much faster than
someone manually
entering large amounts
of text
All documents need to be
checked over carefully
and then manually
corrected
The latest software can
recreate tables and the
original layout
If the original document
is of poor quality or the
handwriting difficult to
read, more mistakes will
occur
Not worth doing for small
amounts of text
25. Optical Mark Recognition
Optical Mark Recognition, OMR is the
process of gathering information from
human beings by recognizing marks on a
document. OMR is accomplished by using
a hardware device (scanner) that detects
a reflection or limited light transmittance
on or through piece of paper. OMR allows
for the processing of hundreds or
thousands of physical documents per
hour.
26. Advantages of OMR Disadvantages of OMR
A fast method of inputting
large amounts of data - up to
10,000 forms can be read per
hour depending on the
quality of the machine used.
If the marks don't fill the
space completely, or aren't in
a dark enough pencil, they
may not be read correctly
Only one computer needed to
collect and process the data
Only suitable for recording
one out of a selection of
answers, not suitable for text
input
.
OMR is much more accurate
than data being keyed in by a
person
The OMR reader needs the
answers to be on the
prepared forms which will all
be identical to one another.
You can't just pick up a blank
sheet of paper and mark
your answers on it.