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Computer basics: Components of a computer

The computer becomes an essential device in our day to day life. I am a regular user of PCs in my daily routine. Hence, I want to share my knowledge of computer basics with you. This article will help you to understand the different components of a computer.

The term computer acquires from a Latin word. The Latin word is ‘computare’. It means, to calculate or to count, or to sum up.

What is a computer?

If someone asks you, ‘What is a computer?’ then the answer is here. You can reply to the short answer:

“A computer is a machine.”


“A computer is an electronic device.”

Definition of Computer

A computer is an electronic device that accepts data from input devices. It processes these data as per instructions and produces the result as output.

A computer can perform a variety of operations according to a set of instructions. A computer can do the following functions:

  1. It can accept data.
  2. It can store data
  3. A computer can process data as desired
  4. It can retrieve the stored data as and when required
  5. It can print the result in the desired format

What is a program?

A program is a set of instructions.

What is Instructions?

Commands that tell the computer what to do are called instructions.

Who is the father of computer?

Charles Babbage (1791-1871) is the Father of the computer. He has been well known as the inventor of the analytical engine.

Block Diagram of Computer

The block diagram of a computer system gives you the pictorial representation of a computer that how it works.

Block diagram of a computer
Fig: Block diagram of a computer

The above figure shows the simple arrangement of different units of a computer.

The dotted lines represent the control exercised by the control unit.

The solid lines represent the flow of instructions and data.

Components of a computer

There are three main components of a computer.

  1. Input Unit
  2. Central Processing Unit
  3. Output Unit

1.Input Unit:

A computer needs data to perform a task. With the help of the input unit, a user can instruct the computer to do some piece of works for him. There are different input devices used in a computer system.

Following are the list of input devices:

  • Mouse – a pointing device.
  • Keyboard – contains the alphabet, digits, special characters, function keys, and some control keys.
  • Joystick – used for playing games.
  • Light pen – a photosensitive pen-like device.
  • Scanner – used to enter information directly into the computer
  • Optical Mark Reader (OMR) – used for recognizing the prespecified type of mark made by pencil or pen.
  • Web camera – to accept images or videos just by focussing on an object.
  • Video Camera – takes continuous pictures and generates a signal for display on the monitor.
  • Voice Input and Recognition System – converts human speech to the electrical signals.
  • Bar-code reader – used to read barcoded data.
  • Magnetic Ink character recognition (MICR) – detects the special encoded characters on bank cheques and deposit slips.

We can say input unit component is the link between the user and the computer.

2.Central Processing Unit (CPU)

This one is the second component of a PC. Central Processing Unit (CPU) is the brain of the computer. It is the key unit you can find inside the PC. 

The primary function of the CPU is to run programs and control the operation of all other parts of a computer.

Following are the major section of a CPU:

  1. Arithmetic and Logic Unit (ALU)
  2. Control Unit
  3. Memory Unit

1.Arithmetic and Logic unit (ALU)

The arithmetic logic unit performs all the actual execution of instructions inside the computer. ALU performs arithmetic and logical operations.

The basic arithmetic operations are, add, subtract, multiply, divide.

And the logical operation are less than, equal to, or greater than.

2.Control unit (CU)

The control unit is responsible for controlling the entire working for the computer. It controls the transfer of data between PC memory and input/output devices.

Control unit accepts data from the input devices and forwards it to the processor.

CU also transmits the processed data to the proper output device to reply to the user.

3.Memory Unit

This unit is essential for the computer. PC needs memory to store data. The memory unit helps the user to store data inside the PC.

Computer memory is of two types:

  • Primary Memory (e.g. RAM).
  • Secondary Memory (e.g. ROM).

If you are interested, you can check to know more about the different types of computer memory.

3.Output Unit

The output unit is the final component of a PC. The output unit is responsible for presenting information to the user in the proper format.

After processing data, a PC supplies the resultant information to the proper output devices.

Following are the list of computer output devices:

  • Printer provides information in a readable form.
  • Speaker – used to get audio.
  • Plotters – used to print good quality graphics objects.
  • Multimedia Projector – used to project information.
  • Speech Synthesizer – converts textual data into spoken sentences.

Types of computer

You can find various types of PCs in the world. And they can perform different types of functions in our daily life.

The two basic types of computer are the following:

  1. Analog computer: The computer that processes analog signals is known as Analog computer.
  2. Digital computer: The computer that processes digital signals is known as a Digital computer.

Following are the some examples of Digital Computer:

  1. Supercomputer
  2. Mainframe computer
  3. Minicomputer
  4. Microcomputer
  5. Personal computer
  6. Desktop Computer
  7. Laptops
  8. Palmtops


Finally, a computer may be defined as a device that operates upon data. In general terms, a computer refers to an electronic data processing machine used for a wide range of activities.

Hope, you have understood the basics of computer and different components of a computer.

If you have trouble maintaining your PC, then here I have a solution for you. You can use these tips to maintain your computer or laptop.