3. Input devices:
An input device is any hardware component that
allows you to enter data and instructions into a
computer. Five widely used input devices are the
keyboard, mouse, microphone,scanner,and Web cam.
4. Scanner:
Scanner is an input device used for
direct data entry from the source
document into the computer
system. It converts the document
image into digital form so that it
can be fed into the
computer.Hand-held scanners are
commonly seen in big stores to
scan codes and price information
for each of the items
5. Web Cam:
A webcam – short for ‘web camera’ –
is a digital camera that’s connected
to a computer. It can send live
pictures from wherever it’s sited to
another location by means of the
internet. Many desktop computer
screens and laptops come with a
built-in camera and microphone, but
if yours doesn’t, you can add a
separate webcam at any time.
6. Keyboard:
A keyboard is the set of typewriter-
like keys that enables you to
enter data into a computer and
other devices. Computer keyboards
are similar to electric-typewriter
keyboards but contain additional
keys. The keys typically found on
computer keyboards are often
classified as follows:
Alphanumeric keys: The letters
and numbers on the keyboard.
Punctuation keys: The
comma,semicolon, and similiar
keys.
Special keys: This includes
the function keys,control
keys, arrow keys, caps Lock key,
and so on.
7. Mouse:
A device that controls the
movement of the cursor or
pointer on a display screen. A
mouse is a small object you can roll
along a hard, flat surface. Its name
is derived from its shape, which
looks a bit like a mouse, its
connecting wire that one can
imagine to be the mouse's tail. As
you move the mouse, the pointer
on the display screen moves in the
same direction.
8. Output Device:
An output device is an electromechanical device
which accepts data from a computer and
translates them into a human acceptable form.
Examples of output devices are printer,monitor,
speakers.
Output generated by output device classified into
two types:
1) Soft-copy output-Output which is not
produced on a paper is known as soft-copy
output. They are temporary in nature.
2) Hard-copy output-Output which is produced
on a paper is known as hard-copy output. They
are permanent in nature.
9. LED Monitors:
An LED monitor display is a flat screen, flat
panel computer monitor or television. It has a
very short depth and is light in terms of weight.
The actual difference between this and a
typical LCD monitor is the backlighting. The first
LCD monitors used CCFL instead of LEDs to
illuminate the screen.
10. Liquid Crystal Display:
Liquid crystal display screen contains a
substance called liquid crystal. The molecules
of this substance line up in such a way that the
light behind the screens blocked or allowed to
create an image. LCDs provide a sharper
picture than CRTs and emit less radiation.
LCD displays requires less power and take up
less space than CRT.
11. Printers:
A Printer takes print commands from a
computer and print out text / images on a
paper. Different types of printers are available
for various purposes. A printer for office use
must be heavy duty and fast while for
photographs it must produce high quality
prints. Dot-Matrix, Ink-Jet, Laser-Jet are the
different types of printers
12. Speakers:
A hardware device connected to a
computer's sound card
that outputs sound generated by
the computer. When computers
were originally released, they
had on-board speakers that
generated a series of different
tones and beeps. As multimedia
and games became popular, higher
quality computer speakers began
to be released that required
additional power.
13. Storage Devices:
A storage device is any computing
hardware that is used for storing, extracting
data files and objects. It can hold and store
information both temporarily and
permanently, and can be internal or external
to a computer, server or any similar computing
device.
There are two different types of storage
devices:
1)Primary Storage devices.
2)Secondary Storage Devices.
Primary Storage devices.
Generally smaller in size, are designed to hold
data temporarily and are internal to the
computer. They have the fastest data access
speed, and include RAM and cache memory.
14. Secondary Storage devices:
These usually have large storage
capacity, and they store data permanently.
They can be both internal and external to the
computer, and they include the hard disk,
compact disk drive and USB storage device.
15. Processing Devices:
A processing device is any component in a
computer that manages the storage and
retrieval of information. Typical examples of
processing devices include central-processing
units, computer motherboards, network cards,
graphics-processing units and sound cards.
CPU is the abbreviation for central processing
unit. The CPU is the brains of the computer
where most calculations take place.
Two typical components of a CPU are the
following:
The arithmetic logic unit (ALU), which
performs arithmetic and logical operations.
The control unit (CU), which
extracts instructions from memory and
decodes and executes them, calling on the
ALU when necessary.
