3. WHAT ARE INPUT – OUTPUT (I/O) DEVICES ?
The computer is a very versatile machine. It can easily process different types of data. To work with these data,
we require different types of devices. These devices can help us enter data into the computer. These devices are
called INPUT and OUTPUT Devices.
The devices that are used to display the information of the results are known as output devices. While the
devices whose main function is to give instructions and data to the computer are called input devices.
They mainly cover devices like mouse, keyboard, printer, speaker, joystick, etc which can be used with a
computer.
4. I N P U T D E V I C E S
In computing, an input device is a piece of computer hardware equipment
used to provide data and control signals to an information processing
system such as a computer or information appliance. Examples of input
devices include keyboards, mouse, scanners, digital cameras, joysticks,
and microphones.
Input devices can be categorized based on:
modality of input (e.g. mechanical motion, audio, visual, etc.)
whether the input is discrete (e.g. pressing of key) or continuous (e.g. a
mouse's position, though digitized into a discrete quantity, is fast enough to
be considered continuous)
the number of degrees of freedom involved (e.g. two-dimensional traditional
mice, or three-dimensional navigators designed for CAD applications)
5. TYPES OF INPUT DEVICES:
KEYBOARD : ‘
Keyboards' are a human interface device which is represented as a layout of buttons. Each
button, or key, can be used to either input a linguistic character to a computer, or to call upon
a particular function of the computer. They act as the main text entry interface for most users.
Traditional keyboards use spring-based buttons, though newer variations employ virtual keys,
or even projected keyboards. It is typewriter like device composed of a matrix of switches.There
also happens to be another keyboard that is like an input device for musical instrument which
helps to produce sound.
Examples of types of keyboards include:
o KEYER
o KEYBOARD
o LIGHTED PROGRAM FUNTION KEYBOARD (LPFK)
o THUMB KEYBOARD
6. MOUSE :
Pointing devices are the most commonly used input devices today. A pointing device is any human interface device that
allows a user to input spatial data to a computer. In the case of mouse and touchpads, this is usually achieved by detecting
movement across a physical surface. Analog devices, such as 3D mice, joysticks, or pointing sticks, function by reporting their
angle of deflection. Movements of the pointing device are echoed on the screen by movements of the pointer, creating a
simple, intuitive way to navigate a computer's graphical user interface (GUI).
Pointing devices, which are input devices used to specify a position in space, can further be classified according to:
o Whether the input is direct or indirect. With direct input, the input space coincides with the display space, i.e. pointing is
done in the space where visual feedback or the pointer appears. Touchscreens and light pens involve direct input. Examples
involving indirect input include the mouse and trackball.
o Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with a mouse that can be lifted and
repositioned)
• Examples of types of pointing devices include:
mouse
touchpad
pointing stick
touchscreen
trackball
7. MICROPHONE :
an input device that allows users to input
audio into their computers. Here are some
uses of the microphone:
Audio for video
Computer gaming
Online chatting
Recording musical instruments
Recording voice for dictation, singing
and podcasts
Voice recorder
Voice recognition
VoIP – Voice over Internet Protocol
DIGITAL CAMERA :
is an input device that takes pictures digitally.
Images are stored as data on memory cards. It
has an LCD screen that allows users to preview
and review images. Digital cameras have
become popular over film cameras because of
the following features:
LCD screen – allows users to view the photos
and videos immediately
Storage – can store thousands of pictures
Picture development – allows users to
choose and pick which pictures to develop
Size – takes up less space and can be easily
carried
8. SCANNER :
is an input device that reads an image and
converts it into a digital file. A scanner is
connected to a computer through USB. There
are different types of scanners:
Flatbed scanner – uses a flat surface to scan
documents
Sheetfed scanner – like a laser printer where
paper is fed into the scanner
Handheld scanner – the scanner is dragged
over the page to be scanned
Card scanner – for scanning business card
TOUCHSCREEN :
is an input device that allows users to interact with a
computer using their fingers. It is used widely in
laptop monitors, smartphones, tablets, cash registers
and information kiosks. Most common functions of
touchscreens are as follows:
Tap
Double-tap
Touch and hold
Drag
Swipe
Pinch
BARCODE READER :
also known as barcode scanner or point of sale (POS)
scanner, is an input device capable of reading
barcodes.
BIOMETRIC DEVICES :
is an input device used to input biometric data
into a computer. Here are the types of biometric
devices:
Face scanner
Hand scanner
Finger scanner
Voice scanner
9. TYPES OF OUTPUT DEVICES :
Computer output devices are all peripheral hardware, and
are connected to a computer by cables, or by wireless
networking.
MONITOR :
This is the most
common computer output device. It
creates a visual display by the use of
which users can view processed
data. Monitors come in various sizes
and resolutions.
Common Types of Monitors :
Cathode Ray Tube – this uses
phosphorescent dots to generate the
pixels that constitute displayed
images.
Flat Panel Screen – this makes use of
liquid crystals or plasma to produce
output. Light is passed through the
liquid crystals in order to generate
pixels.
PRINTER : this device generates a hard copy
version of processed data, like documents and
photographs. The computer transmits the image data
to the printer, which then physically recreates the
image, typically on paper.
Types of Printers
Ink Jet – this kind of printer sprays tiny dots of ink onto
a surface to form an image.
Laser – this type utilises toner drums that roll through
magnetized pigment, and then transfers the pigment
onto a surface.
Dot Matrix – dot matrix printers utilise a print head to
set images on a surface, using an ink ribbon. These
printers were commonly used between 1980 and
10. SPEAKER :
speakers are attached to computers to
facilitate the output of sound; sound
cards are required in the computer for
speakers to function. The different
of speakers range from simple, two-
speaker output devices right the way up
to surround-sound multi-channel units.
HEADSET :
this is a combination of speakers and
microphone. It is mostly used by
gamers, and is also a great tool for
communicating with family and
friends over the internet using some
VOIP program or other.
PROJECTOR :
this is a display device that projects a
computer-created image onto
another surface: usually some sort of
whiteboard or wall. The computer
transmits the image data to its video
card, which then sends the video
image to the projector. It is most
often used for presentations, or for
viewing videos.
PLOTTER :
this generates a hard copy of a digitally
depicted design. The design is sent to
the plotter through a graphics card, and
the design is formed by using a pen. It
is generally used with engineering
applications, and essentially draws a
given image using a series of straight
lines.
11. INPUT – OUTPUT (I/O) DEVICES :
Input/Output devices don’t only produce output, but can also be used
as storage and input devices. The computer transmits data to the drive,
where it is saved and can be later accessed.
Examples of I/O devices are CD drives, DVD drives, USB drives, hard disk
drives (HDDs), and floppy disk drives.
CDs and DVDs are two kinds of optical disc which save data in a digital
format. Data is written onto the disc using a laser writer that embeds the
data directly into the disc’s coating.
A floppy disk is a magnetic storage device. A layer of magnetised material
is placed within a proactive plastic casing. The computer then embeds the
data into the magnetized material, by using a writing head.
