Computer is an electronic device that stores,
retrieves, and processes data, and can be
programmed with instructions. A computer is
composed of Hardware and Software.
A computer provides three basic benefits:
Speed: Computers work at very high speeds and are
much faster than human.
Accuracy: Computers rarely make mistakes. In fact,
most computer errors are caused by human faults.
Diligence: Unlike humans, computers simply do not get
board or tired.
INPUT DEVICE OUTPUT DEVICE
1. KEYBOARD 1. VDU (Monitor)
2. MOUSE 2. PRINTER
3. MICROPHONE 3. SPEAKER
4. JOYSTICK 4. HEAD PHONE
6. WEB CAMERA
MOUSE :- A Mouse is an input device There are
many types of mouse like Optical Mouse and Ball
Ball Mouse Optical Mouse
The Keyboard is a input device. This is a
components that closely resemble a typewriter
console. The keyboard provides different keys to
perform various operations.
Data that has been processed needs to be
displayed to the user. This is done using the
monitor or the VDU. The VDU is similar to a TV
screen and can display both text and graphic
images. The display can be either in black & white
CRT Monitor LCD Monitor
Cethord Ray Tube Liqued Cristal Display
Printer is a output device. Using the printer, you
can obtain output on paper. The printers
commonly used with the, ink-jet and the laser
A Microphone is an input device that allows a user
to speak to the computer to enter data and
instructions into the computer or it is used to
A joystick is a pointing device with a vertical lever
mounted on a base. It is mainly used for computer
games and ultrasound scanners in hospitals.
A scanner is a input device used to capture
information, such as, photographs and documents
on paper and translate the information into a raster
(bitmap) computer image.
You can use speaker on a multimedia machine to
listen to the sound files, which can be audio,
recorded by a microphone or audio CDs.
Motherboard :- The System Unit is the one of the
most important component of the System Unit.
This is the Heart of the Computer.
CPU :- CPU is the Brain of the Computer and is
placed inside the System Unit. There are many
models of CPU like…
I. Pentium I
II. Pentium II
III. Pentium III
IV. Pentium IV
When you open the system unit, a large board
containing of tiny electronic circuits components are
visible. The components of the motherboard are.
III. Clock chip
IV. Rom chip
V. Memory: RAM and ROM
The Data is stored in storage devices for processing
data as well as for future references. There are two
type of Storage Device.
Primary Storage Device :- The primary storage device
for a computer is Random Access Memory (RAM).
Secondary Storage Device :- This is a permanently
storage memory. Like
1. Hard Disk
2. Floppy Disk
3. Compact Disk (CD)
4. Pen drive
5. Memory Card
The Internal power supply it called SMPS
SMPS convert the AC input into DC output.
SMPS provides cable connectors to supply the
required voltage to other internal components
like the Hard disk, CD drive and external device
such as Keyboard and Mouse.
The SMPS has a small Fan, called Exhaust Fan,
Its function is to cool the SMPS unit.
We have many Storage device in our
I. FLOPPY DISK
II. HARD DRIVE
III. CD-ROM SYSTEM
These are permanently (Secondary) storage
The internal memory of a PC is present on the
motherboard in the form of chips. The computer used
two types of internal memory.
I. RAM (Random Access Memory)
II. ROM (Read Only Memory)
RAM :-This is the memory that the computer use for
storing the programs and their data while working on
them. So, if you are drafting a latter using a word
processor, such as MS WORD, you are working with a
document loaded into the RAM.
Floppy disk is a storage device, this is a secondary
storage device. This is a non- volatile memory.
Floppy Disks come in two sizes. Its covered with a
square protective jacket.
The Hard Disk is collection of the disk known as
platters. Hard disk located inside the system unit.
Hard disk is a non-volatile memory.
The hard disk is a high storage capacity disk and is
permanently placed inside the system unit.
CD-ROM (Compact Disk Read Only Memory) is a
very popular storage medium. This is a secondary
storage device. To read a CD, you need an input
device called CD-ROM drive. You can make the
data CD, photo CD, Video CD.
A Computer uses its software to store, process, and
retrieve information. Computer software can be divided
into two types,
I. Application Software
II. System software
Application software refers to the software that
enables user to perform specific task. For example,
MS Word is used to create and edit document.
System software refers to the software that enables a
computer to function. For example, Windows
These are other helpful
Cut: This is used to cut things out of your
Copy: this is used to copy from
one portion of your project to
Paste: When you cut or copy something from
your project, it is put on an “imaginary”
clipboard. The paste button retrieves it from the
clipboard and places it in your project