# Block diagram of computer

A computer is a device, which is used to manipulate the information or for doing calculations and other tasks, but every task that is given to the computer, is processed in CPU. We can easily understand the processing of all functions in a computer system with the help of block diagram of computer.

#### CPU: Central Processing Unit.

The CPU is the brain of a computer. As humans need the brain to complete every task, similarly computers need CPU to complete its tasks. Every instruction that the user gives to the computer goes in CPU for processing to get the output or result.

To explain the processing of the CPU, we have this block diagram. Block diagram of computer gives us a quick overview of its processing.

In this process, there are three steps:

To give input,

Processing in CPU,

Receiving output.

#### 1. Input unit:

The information or instructions that the user enters in the computer system is called input. The devices which are used to enter instructions are called input units. Input unit like a keyboard is used for typing input. For example: If we type, “2+2” from the keyboard, it will be the input.

#### 2. Processing in CPU:

In CPU there are three units which work together. These units are:-

CU: Control unit

ALU: Arithmetic Logic Unit

Memory Unit

When we give input, first it goes to the Memory Unit which stores the information or input.

After that Input goes to CU from the memory unit.

CU stands for control unit.

Here the entire operation or processing of the given input is controlled. It obtains the instructions from the memory, interprets them and directs the operation or process of the computer. It also controls all devices such as memory units, input and output devices connected to the computer. In simple words, it controls the given input or instructions by the user to the computer.

Then input goes to ALU.

ALU performs all the arithmetic operations such as addition, subtraction, multiplication and division.

It also performs logical operations for comparison.

Like : And or Not,  =,<, > .

For example, if we give instruction “2+2”, the ALU will perform arithmetic/mathematical function and calculate it.

When the calculation is done, it proceeds to the next step.

The last step is the output unit. After all the processing, from typing input and processing in CPU, it gives output.

As we gave input “2+2”, after processing in the CPU, we got output 4.

The process goes like, Input  > CPU  >  output .

Input is 2+2  > processing in CPU > output is 4

#### 3. Output units

Output units/devices receive information from the CPU and show it on the computer screen. Then we can save this information in the external storage. The examples of output devices are, monitor, printer etc.

So, this was all about block diagram of computer. For more knowledge of basic computer, join our course now.