Computer-Basics - Ts Read

Friday, 26 May 2017


Hello friends welcome to 

Computer has three main parts - input devices, output devices and processing devices (system unit). System Unit is a box that contains the following devices :

1. Motherboard 2. Power-supply unit 3. Main Memory 4. CPU 5. Input-Output Ports 6. Hard Disk 7. Disk Drive 8. Video Card 9. Expansion Slot 10. Battery

1. Motherboard 

A piece of fibre glass is found in the system unit. This piece is called the motherboard .It is a printed circuit board or pub, where all the electrical circuits are printed on the board. The various components needed to run the computer are mounted on it.
All the electric components are mounted on it. As the fibre glass does not conduct electricity , each component remains safely insulated from other components.

2. Power-supply unit

All the electric components need electricity to perform their functions. Some components need 5- volts supply and some require 12-volt supply. Some require very high voltage current like household applicances.
The components of a Personal Computer (pc) need 5-volt and 12 - volt supply. Since they need low voltage current , a current is required . This device is called the power supply unit . It is placed inside the system unit.

3. Main Memory

The main memory is used to store information and instructions that instruct the computer what to do and how to process the data.
This memory has two parts :

(i)RAM (Randam Access Memory) is a volatile memory , i.e., when the is switched off , all the data in RAM  is lost . RAM reads the data form the hard disk of the computer . Computer takes the information and instruction and instruction through the RAM .

(ii) ROM (Read Only Memory) is a non- volatile memory .It consists of fixed data or instructions . ROM is put in when the couputer is manufactured and contains data needed to start and run a computer .

4. CPU

The full form of CPU is Central Processing Unit . It is the brain of the computer. It does all the thinking for the computer . It carries out all the instructions given by the operator.

It has two parts :
(i) The Control Unit
(ii) The Arithmetic and Logical Unit (ALU)

Control Unit controls everything that happens inside the computer. It also fetches data from the memory , sends it to ALU for processing and then sends the processed data back to the memory. The full form of ALU is Airthmetic and Logical Unit . All the arithmetical and logical problems are solved in it .


All the peripherals are connected to the system unit by ports . So a part is a connector between the system unit and other devices of a computer like the printer. A cable is used to connect the device to the system unit .
parts are of two types - serial port and parallel port . serial or parallel cables depend no the mode of data - transmission . Parallel ports is used , when data is transmitted over parallel signals . For example , printer is used on a parallel port.

If the data is sent over the serial signals, serial port is used . For example , Mouse is connected though serial port .

6. Hard Disk

The hard disk is the permanent storage unit of the computer . It can hold large amounts of data and instructions . There may be only one hard disk or more than one in the system unit.

7. Disk Drive

Disk drive is used to read and write a floppy or a compact disk . A floppy or a CD is inserted into the drive . A drive consists of 3 parts :

1. A slot that accepts the disk .
2. A motor that spins the inserted disk .
3. A device that moves across the disk to read or write the data stored on it .

8. Video Card

You already know that all the information is stored in the computer's memory . This information is useful, when you see it on monitor . Monitor displays your informaition , when you use video card . Video card is also called Display adaptor  card . It links the computer's memory to monitor.

9. Expansion Slot

An expansion slot is where an expansion card can be fitted. Each expansion slot leads to a bus on the motherboard . The bus is a channel or path which enabels the various parts of a computer to communicate with one another . It serves as a road along which signals are sent .

10. Battery

when you use a computer, you must have noticed that computer always shows the connect date and time even if it has not been switched on for many days.

What is the reason behind this ? here is what keeps your date and time updated ! A device is placed inside the system unit . It provides Direct current electricity . It is known as a battery . This battery powers the clock and date . It is the current from this battery that keeps them running even when the computer is turned off.