Mouse:
A mouse is a small device used to point to and select
items on your computer screen. Although mice come in many shapes, the typical
mouse does look a bit like an actual mouse. It's small, oblong, and connected
to the system unit by a long wire that resembles a tail. Some newer mice are
wireless.
Basic parts:
A mouse typically has two buttons: a primary
button (usually the left button and a secondary button (usually the right
button). The primary button is the one you will use most often. Most mice also
include a scroll wheel between the buttons to help you scroll through documents
and Web Pages more easily. On some mice, the scroll wheel can be pressed to act
as a third button. Advanced mice might have additional buttons that can perform
other functions.
Keyboard:
A keyboard is used mainly for typing text into
your computer. Like the keyboard on a typewriter, it has keys for letters and
numbers, but it also has special keys:
• The function keys, found on the top row, perform different
functions depending on where they are used.
• The numeric keypad, located on the right side of most
keyboards, allows you to enter numbers quickly.
• The navigation keys, such as the arrow keys, allow you to
move your position within a document or webpage.
Typing text:
Whenever you need to type something in a
program, e mail message, or text box, you'll see a blinking vertical line.
That's the cursor, also called the insertion point. It shows where the text
that you type will begin. You can move the cursor by clicking in the desired
location with the mouse, or by using the navigation keys
Tracker ball:
Tracker ball is an input device that is mostly used in
notebook or laptop computer, instead of mouse. The tracker ball also called as
crystal ball is another form olfactory. It is a ball which is half inserted and
by moving fingers on the ball pointer can be moved.
Joystick:
Joystick is similar to a large toggle switch. This is
normally used for playing computer games. It is like a rod insert into a pad.
By movement of rod pointer can be moved on screen. It is stick set in two
crossed grooves and can be moved left or right, forward or backward. It is
difficult to employ a joystick to control the absolute position of a screen
cursor directly because a slight hand movement is amplifier 5 or 10 times and
hence the position of careen cursor.
Scanner: A scanner allows you to scan documents, pictures,
or graphics and view them on the computer.
You can also use software to edit the items you scan.
• Used to
put printed pictures and text into a computer
• Converts
an image into dots that the computer can understand
• To scan
text, optical character recognition (OCR) software is needed
Digital Camera
• Used to
take electronic pictures of an object
• The
pictures taken by a digital camera can be used directly by a computer
Bar Code Reader (BCR):
This device is getting very popular these days bar code
reader is a device used for reading bar coded data i.e. alternating lines &
spaces which represent data in binary form.
Items having the codeine passed over the bar code reader the reader
automatically decoder the stripes & passes the data to the computer. The
most widely known bar code is universal product code which now appears on
almost all retail packages in U.S.A. these bars are decodes as 10 digits. Their
use is getting increased in super market & other big shops etc.
Optical Mark Reader (OMR):
OMR is a device which can detect
the presence or absence of a pencil or pen mark on a paper. Light is shown onto
the marked paper & the reflected light is observed. This technique of mark
recognition is possible only when pre-determined card or forms are used &
the marks are made in specified portions or boxes on the documents.
OMR is extremely useful for reading answer to questions in a
test or survey. The student can select the appropriate box & fill it b soft
pencils. OMR is a slow process. The rate of data transfer Is 200 to 250
documents per minute.
MICR:
MICR stands for magnetic Ink Card reader. It use
special ink that contains particles of magnetic material reading process is
called magnetic ink character recognition. This method is very common in
computerized bank for writing cheque number or draft number & reading
cheque & deposit steps of the banking industry. Major merit of MICR is
machine readable. So it is fast & less recognizing only a few characters
styles. It is used to print the identification marks so that character
formation is slightly more complex & needs accuracy.
Advantages of MICR:
• The
identification codes can be read by the machine as well as human beings.
• Error
detection & correction becomes easier.
• Extremely
beneficial to banking industry.
