What is CPU – Central Processing Unit ? Major Sections of CPU

What is CPU – Central Processing Unit? What are the major sections of CPU?

The control unit and the arithmetic unit of a computer system are jointly known as central processing unit (CPU). The CPU is the controlled center for a computer.

It guides, directs and governs its performance. Therefore it is also known as the Brain of the Computer.

In the computer all the major calculations and comparisons are made inside the CPU and the CPU is responsible for activating and controlling the operations of other units of the computer system.


what is cpu


The major section of a CPU are:

  1. Arithmetic Logic Unit (ALU)
  2. Control Unit (CU)


1. ALU(Arithmetic and Logic Unit):

The ALU performs the arithmetic and logic operations on the data as a result of the execution of decoded instructions. To be more precise, calculations are performed and all decisions are made in ALU.

It can perform all arithmetic calculations. e.g. addition, subtraction, multiplication, division etc. and logical operations (>, <, > =, < = ! =) The result of logical operations is either True or False.


2. CU(Control Unit):

The control unit controls and guides the interpretations, flow and manipulation of all data and information.

The CU sends control signals until the required operations are done properly by ALU and memory.

Although control unit does not perform any actual processing on the data, the control unit acts as a central nervous system, for the other components of the computer system.

It manages and co-ordinates the entire computer system. It obtains instructions from the program stored in main memory, interprets the instructions, and issues signals, which cause other units of the system to execute them.

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FAQ (Frequently Asked Questions)

Q1. What do you mean by Input Units and what are their functions?

Ans. Input Units are those through which you can enter/give your data and instructions to the computers. Various types of input units available are mouse, keyboard, joystick, digitizer, scanner etc.

Q2. What are the Functions of Input Units?


  1. It takes the data from the user.
  2. It converts it into machine/ binary language.
  3. It supplies that binary data to processor for further processing.

Q3. What do you mean by output devices and what are its functions?

Ans. The output devices receive results and other information from the computer and provide them to the users. Various output devices available are Monitor, printers, plotters etc.

Q4. What are the Functions of Output Unit?


  1. It takes the data from the processor.
  2. It converts it into human acceptable form.
  3. It supplies that results to the outside world.

Q5. What are three components of the central processing units?

Ans. The three components of the central processing units are control unit (CU) Arithmetic logic unit (ALU) and main/primary memory.

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An aspiring BCA student formed an obsession with Computer/IT education, Graphic Designing, Fitness, YouTube and Blogging, and Helping Beginners to learn these skills and implement them in their life.

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