The document discusses various types of computer input and output devices. It describes keyboards, mice, scanners, joysticks, light pens, and other input devices used to communicate data and instructions to computers. Output devices discussed include monitors, printers, speakers, and projectors used to display or present the processed data to users. The key functions and characteristics of different input and output hardware are provided.

2. An input device is a hardware or
peripheral device used to send data
to a computer. An input device
allows users to communicate and
feed instructions and data to
computers for processing, display,
storage and/or transmission.

3.  Keyboard
 Mouse
 Scanner
 Joystick
 Light Pen
 Digitizer
 Microphone
 Magnetic Ink Character Recognition (MICR)
 Optical Character Reader (OCR)

4.  Text Input devices - Keyboard
 Graphical Input Devices – Scanner, OCR, OMR,
MICR, Digital Camera
 Cursor Control Input Device – Mouse, Joystick,
Trackball, light pen
 Sound Input Device - Microphone

5.  The keyboard is a basic input device that is used to
enter data into a computer or any other electronic
device by pressing keys. The layout of the
keyboard is like that of traditional typewriter.
 It has different sets of keys for letters, numbers,
characters, and functions. Keyboards are connected
to a computer through USB or a Bluetooth device
for wireless communication.
 A standard keyboard has 101/102 keys and is also
known as QWERTY Keyboard. In QWERTY each
character represents the first six alphabetic keys of
the keyboard of the top row.

6. The keys on the keyboard are as follows −
 Typing Keys
These keys include the letter keys (A-Z) and digit keys (09) which
generally give the same layout as that of typewriters.
 Numeric Keypad
It is used to enter the numeric data or cursor movement. Generally,
it consists of a set of 17 keys that are laid out in the same
configuration used by most adding machines and calculators.
 Function Keys
The twelve function keys are present on the keyboard which are
arranged in a row at the top of the keyboard. Each function key has
unique meaning and is used for some specific purpose.
 Control keys
These keys provide cursor and screen control. It includes four
directional arrow keys. Control keys also include Home, End, Insert,
Delete, Page Up, Page Down, Control(Ctrl), Alternate(Alt),
Escape(Esc).
 Special Purpose Keys
Keyboard also contains some special purpose keys such as Enter,
Shift, Caps Lock, Num Lock, Space bar, Tab, and Print Screen

7.  Mouse is the most popular pointing device. It is a
very famous cursor-control device having a small
palm size box with a round ball at its base, which
senses the movement of the mouse and sends
corresponding signals to the CPU when the mouse
buttons are pressed.
 Generally, it has two buttons called the left and the
right button and a wheel is present between the
buttons. A mouse can be used to control the
position of the cursor on the screen, but it cannot
be used to enter text into the computer.
 Mouse has three button- Left Button, Right Button
and Scroll Button.

8.  Mechanical Mouse-A mechanical mouse is a computer mouse that
contains a metal or rubber ball on its under side. When the ball is
rolled in any direction, sensors inside the mouse detect this motion
and move the on-screen mouse pointer in the same direction.
 Optical Mouse- an optical mouse emits a beam of light from its
underside, it uses the light’s reflection to judge the distance and
speed of its travel.
 Wireless (Cordless) Mouse-As the name suggests, this type of mouse
lacks cable and uses wireless technology such as IrDA (infrared) or
radio (Bluetooth or Wi-Fi) to control the movement of the cursor
 Biometric Mouse-the Biometric mouse provides security to your
computer system. It has an integrated fingerprint reader that
permits only the authorized user to access the computer system
with the mouse.

9. Mouse Actions
 Clicking
 Double Clicking
 Dragging
 Right Clicking
 Scrolling

10.  A trackball is an input device used to
enter motion data into computers or
other electronic devices. It serves the
same purpose as a mouse, but is
designed with a moveable ball on the
top, which can be rolled in any direction.
Instead of moving the whole device, you
simply roll the moveable ball on top of
the trackball unit with your hand to
generate motion input.
 This is an input device that is mostly
used in notebook or laptop computer.
 You can place a track ball on any type of
surface including our palm or lap.

11.  Joystick is also a pointing device
which is used to move cursor
position on a monitor screen. It is
input device used in Playing games,
CAD (Computer aided designing)
and flight simulator.
 Joystick is a stick having a spherical
ball at its both lower and upper
ends.
 To make the movement of the
cursor to the desired position we
have a stick which can moved
forward and backward, left or right.

12.  A light pen is a light-sensitive
pointing input device commonly
used to select or otherwise modify
text or data on a screen. Used with
a CRT monitor, these devices were an
early form of manipulating and
highlighting data on the screen.
 A light pen input device used for
personal digital assistants and other
types of handheld computers are pen
based devices.
 The pen does not emit light. The
light sensitive diode at the tip of the
pen senses the light coming from the
screen.
 A light pen may also be used to
describe the pen (stylus) used with
a graphics tablet.

13.  The term light pen may also refer to a pointing
input device utilizing a light that is commonly used
during a presentation. The light pen can be a very
focused flashlight-type of device or a laser pointer,
allowing a user to direct viewers' attention to a
specific area, like a picture or text, in the
presentation.
 The light pen can also be used for graphic work in
CAD (Computer Aided Design). An architect or
engineer can draw directly on the screen with the
light pen.

14.  A scanner is an input device that scans documents such as
photographs and pages of text. When a document is scanned,
it is converted into a digital format. This creates an electronic
version of the document that can be viewed and edited on a
computer.
 When a document is placed inside a scanner, the image is
first scanned and then the scanned data is processed and
sent to a computer system.
 There are various types of scanners:
Flatbed Scanner- Fletbed scanner also called desktop
scanners. They are most commonly used and versatile
scanners. These look like a photocopy machine and produce
high quality images but are more expensive than other
scanners.

15.  Sheetfed Scanner- This scanner scans the paper fed into it. It
is similar to flatbed scanner the only difference is that in this
scanner the document is moved and the the scan head is
immobile.
 Drum Scanner- Drum scanners are medium size scanners.
This type of scanners are used by publishing industry to
capture the detailed image. The technology used by drum
scanner is PMT i.e.
 Hand held Scanner- Some scanners are small hand-held
devices that you move across the paper. These hand-held
scanners are often called half-page scanners beacause they
can only scan 2 to 5 inches at a time.

16.  An output device is an electromechanical device, that receive
information from the computer and translate it from machine
language into a form that humans can read and is suitable for
outside world.
 Output devices can be broadly classified into two types. –
Hard copy output and Soft copy output.
 Soft copy Output- Output which is not produced on a paper is
known as soft copy output. They are temporary in nature. For
example output displayed on a terminal screen are soft copy
output.
 Hard copy output- Output which is produced on a paper is
known as hard copy output. They are permanent in nature.
For example output produced by printers and plotters on
paper are hard copy output.

17.  Monitors
 Printers
 Projectors
 Speakers
 Plotters
 Sound card
 Video card

18.  Monitors, commonly called as Visual
Display Unit (VDU), are the main output
device of a computer. It forms images from
tiny dots, called pixels that are arranged in
a rectangular form. The sharpness of the
image depends upon the number of pixels.
 There are two kinds of viewing screen used
for monitors.
1. Cathode-Ray Tube (CRT)
2. Flat-Panel Display
 Cathode Ray Tube (CRT)- CRT is the
electron beams in a monitor that move
across your screen either interlaced or
non-interlaced, hitting phosphor dots on
the inside glass tube. The picture is an
example of the inside of a computer
monitor that shows the CRT connected to
the screen.

19.  It is a type of vacuum tube which displays images when the
electron beam through electron guns are strikes on
the phosphorescent surface. In other Words, the
CRT generates the beams, accelerates it at high velocity
and deflect it for creating the images on the phosphorous
screen so that the beam becomes visible
 There are two popular approaches for producing color
displays with a CRT are: Beam Penetration and Shadow
masking.
 Flat-Panel Display Monitor- The flat-panel display refers to a
class of video devices that have reduced volume, weight and
power requirement in comparison to the CRT. You can hang
them on walls or wear them on your wrists. Current uses of
flat-panel displays include calculators, video games,
monitors, laptop computer, and graphics display

20.  The flat-panel display is divided into two categories −
Emissive Displays − Emissive displays are devices that convert
electrical energy into light. For example, plasma panel and
LED (Light-Emitting Diodes).
Non-Emissive Displays − Non-emissive displays use optical
effects to convert sunlight or light from some other source
into graphics patterns. For example, LCD (Liquid-Crystal
Device).
 LCD (Liquid Crystal Display) -Stands for "Liquid Crystal
Display." LCD is a flat panel display technology commonly
used in TVs and computer monitors. It is also used in screens
for mobile devices, such as laptops, tablets,
and smartphones.

21.  Printer is an output device, which is used to print information
on paper.
 There are two types of printers −Impact Printers and Non-
Impact Printers
Impact Printers- Impact printers print the characters by striking
them on the ribbon, which is then pressed on the paper.
Example: Dot matrix printer, drum printer , chain printer
Non Impact Printers- These printers prints characters and
graphics on a paper without actually striking the paper. As
there is no contact so these printers produce low noise, low
process control requirements, low energy and low cost
operations. Examples- Laser printer and Thermal printers.

22.  Dot matrix printer (DMP) -A dot matrix
printer (DMP) is a type of printer which
uses pins impacting an ink ribbon to
print. These printers are generally
considered outdated, as they cannot
create high-quality prints and are costly
as well. However, they have a certain
specialty that other printers like inkjet
and laser printers do not have: as they
use impact for printing, they can be
used to print multiple copies of text at
the same time with the help of carbon
copying. Therefore, they are mostly
used in places where multipart forms
are required.
 Daisy wheel printer - Head is lying on a
wheel and pins corresponding to
characters are like petals of Daisy
(flower) which is why it is called Daisy
Wheel Printer. These printers are
generally used for word-processing in

23.  Laser Printers- These are non-
impact page printers. They use
laser lights to produce the dots
needed to form the characters
to be printed on a page.
 Inkjet Printers- Inkjet printers
are non-impact character
printers based on a relatively
new technology. They print
characters by spraying small
drops of ink onto paper. Inkjet
printers produce high quality
output with presentable
features.

24.  A projector is an output
device that can take images
generated by a computer or Blu-
ray player and reproduce them by
projection onto a screen, wall, or
another surface. In most cases,
the surface projected onto is
large, flat, and lightly colored. For
example, you could use a
projector to show a presentation
on a large screen so that everyone
in the room can see it. Projectors
can produce either still (slides) or
moving images (videos). A
projector is often about the size
of a toaster and weighs only a few
pounds