For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations.

4. Keyboard
In computing, a Keyboard is a typewriter-style
device, which uses an arrangement of buttons
or keys, to act as mechanical levers or electronic
switches. Following the decline of punch
cards and paper tape, interaction via tele printer-
style keyboards became the maininput
device for computers.
A keyboard typically has
characters engraved or printed on the keys and
each press of a key typically corresponds to a single
written symbol. However, to produce some symbols
requires pressing and holding several keys
simultaneously or in sequence. While most
keyboard keys produce letters, numbers or signs
(characters), other keys or simultaneous key
presses can produce actions or execute computer
commands.

5. MOUSE
In computing, a mouse is a pointing device that detects two-dimensional motion relative to a surface. This motion is
typically translated into the motion of a pointer on a display, which allows for fine control of a graphical user interface.
Physically, a mouse consists of an object held in one's hand, with one or more buttons. Mice often also feature other
elements, such as touch surfaces and "wheels", which enable additional control and dimensional input.

6. SPEAKER

7. PROJECTOR
A projector or image projector is an optical device that projects an
image (or moving images) onto a surface, commonly a projection
screen.
Most projectors create an image by shining a light through a small
transparent lens, but some newer types of projectors can project the
image directly, by using lasers. A virtual, or retinal projector, is a
projector that projects an image directly on the retina instead of
using an external projection screen.
The most common type of projector used today is called a video
projector. Video projectors are digital replacements for earlier types of
projectors such as slide projectors and overhead projectors. These
earlier types of projectors were mostly replaced with digital video
projectors throughout the 1990s and early 2000s (decade), but old
analog projectors are still used at some places. The newest types of
projectors are handheld projectors that use lasers or LEDs to project
images. Their projections are hard to see if there is too much ambient
light.
Movie theaters use a type of projector called a movie projector.
Another type of projector is the enlarger, a device used to produce
photographic prints from negatives.

8. PRINTER
In computing, a printer is a peripheral which makes a
persistent human readable representation of graphics or
text on paper or similar physical media.[1] The two most
common printer mechanisms are black and white laser
printers used for common documents, and color inkjet
printers which can produce high quality photograph quality
output.
The world's first computer printer was a 19th-century
mechanically driven apparatus invented by Charles
Babbage for his difference engine.[2] This system used a
series of metal rods with characters printed on them and
stuck a roll of paper against the rods to print the
characters. The first commercial printers generally used
mechanisms from electric
typewriter and Teletype machines, which operated in a
similar fashion. The demand for higher speed led to the
development of new systems specifically for computer
use.

9. MONITOR