The term peripherals refers to all hardware
devices that are attached to the computer
and are controlled by the computer system
Peripherals can be classified into input
devices and output devices.
Some can be both an input device and an
An input device is a piece of equipment that enables
data to be entered into a computer for example:
The keyboard is made up of push-button switches
which send a signal to the CPU each time you
Keyboard standards vary with names like Deluxe,
Natural and Cordless.
TYPES OF KEYS IN A KEYBOARD
Alphabet keys: ( A, B, : : : , Z).
Number keys: (1,2,3,….0)
Numeric Keypad: (numeric keys on right
Function keys: F1, F2, : : : on top row.
Special keys: Ctrl, Alt, Shift, backspace.
Arrow keys: Left, Right, Up, Down keys.
It is used to control the cursor or pointer on
the screen and to give commands to the
computer. It allows operations to be
performed without having to remember
complicated keyboard commands.
A roller mouse has a ball that is rolled as the
mouse is moved about on the desktop.
A joystick looks like car’s stick shift.
Controls objects on screen.
Allow us to capture images and transfer
them to a computer in the form of an image
Some digital cameras can
capture small amounts of video.
Scanner is a light sensitive device that helps you
copy or capture images, photos, and artwork
that exist on paper and converts it into digital
form that can be processed and stored by the
A webcam is a video camera that feeds its image
to a computer or computer network. Their most
popular use is the establishment of video links,
permitting computers to act as
videophones or videoconference stations
It is used as an audio-input device. The
function of microphone is to enter/record
sound into computer.
Bar Code Reader
A barcode reader is an electronic device for
reading printed bar codes. Bar code reader
helps identify a product.
Output devices take information within your
computer and present it to you in a form that
you can understand
Main output devices:
The monitor or visual display unit (VDU) is the
most significant output device.
Desktop displays use a cathode
ray tube (CRT)