Digital Computer Block Diagram with Components? Easy Guide!

In this article, we will explain all possible stuffs about what is digital computer; as well as block diagram of digital computer with its components and their functions with ease. This is ultimate blog post over the internet; make ensure that after reading this post; you will definitely completely understood about what is digital computer without any getting hassle.

What is Digital Computer?

Digital computer can define as digital systems that are able to get process information at the higher speed. This computer receives the input data that it can process and finally converts the output data; and send it to the output devices for displaying at the front of you, for example of digital computers are smartphone, PDA, Tablet, PC, and etc.


Digital computer has ability to perform various kinds of tasks within less time duration. So, they are more reliable and capable to execute work for continuous duration without getting any hassle.

Digital computer can receive the input, which are understandable for the users, then input converted into machine language and again convert into simple language that also understandable by the users.

All input and output of digital computer are available into binary code like as 0 and 1; because these types of digital computers are eligible only to understand machine language (0’s and 1’s) format.

Digital Computer Tutorial Headlines:

In this section, we will show you all headlines about this entire article; you can check them as your choice; below shown all:

  1. What is Digital Computer?
  2. Evolution of Digital Computer
  3. What is The First Digital Computer?
  4. Introduction Block Diagram of Digital Computer
  5. Explain Block Diagram of Digital Computer
  • Input Unit
  • Central Processing Unit
  • ALU – Arithmetic Logic Unit
  • CU – Control Unit
  • Memory Unit
  • Primary memory
  • Secondary memory
  • Output Unit
  1. Difference between Digital Systems and Digital Computer
  2. FAQs (Frequently Asked Questions)
  • What is digital computer with example?
  • What is digital computer and digital system?
  • What are the components of a digital computer?

Let’s Get Started!!

Evolution of Digital computer

The evolution of digital computers, as following:

First Generation (1940s-1950s): Used vacuum tubes, with main memory consisting of magnetic drums and magnetic tapes. Examples include ENIAC and UNIVAC1.

Second Generation (1950s-1960s): Utilized transistors, with the introduction of magnetic core memory.  In this generation, it was saw the usage of high-level programming languages and the introduced of minicomputers like as IBM 360 and PDP-11.

Third Generation (1960s-1970s): Marked by the use of integrated circuits (ICs) and magnetic tape/disk memory. These computers became cheaper in cost, smaller and more efficient, along with enhancing the reliability and speed.

Fourth Generation (1970s-Present): Characterized by microprocessor-based systems, leading to the development of personal computers. This generation was getting the focus on the improvement in size, speed, and efficiency; along with the introduction of several input/output devices and high-level programming languages.

Fifth Generation (Present & Future): Focuses on artificial intelligence-based systems.

What is The First Digital Computer?

The first digital computer developed by John Vincent Atanasoff in 1940s; and Clifford E.Berry one of their students was helping for inventing. The first electronic digital computer assigned the name as ABC (Atanasoff Berry Computer).

This digital computer had weight approximate 700 pound and was eligible to solving up to 29 simultaneous linear equations.


Traditional digital computer has no Central Processing Unit, but it was going to use Vacuum tubes for executing digital computation. The first digital computer’s speed had 30 actions per seconds.

Introduction Block Diagram of Digital Computer

A block diagram of digital computer displays the internal structure of the computer, as we as the block diagram provides the quick overview of internal working work flow of computer system from inserting data to retrieving the desired output.


Digital computer system performs all their tasks as block-wisen so here we will show you ‘Block Diagram of Digital Computer‘.

Explain Block Diagram of Digital Computer

Digital Computer system performs all tasks along with the combination of major four components, Therefore here we will cover all possible things about components of block diagram of digital computer along with their functions; below shown all things step by steps, you can read them:

  1. Input Unit
  2. Central Processing Unit
  • ALU – Arithmetic Logic Unit
  • CU – Control Unit
  1. Memory Unit
  • Primary memory
  • Secondary memory
  1. Output Unit

Components of Block Digital Computer with Their Functions:

In this section, we will guide you about all components of digital computer with their functions in detail; you can read them:

Input Unit

Input Unit contains the input devices like as scanner, joystick, keyboard, mouse, etc. These input devices allow to user for inserting the instruction or information into the computer system.

Input unit plays the role as a mediator of communication that gets the data from user to the computer system for organized manner for processing.

Input Unit functions are

  • Computer receives the data through input devices like as mouse, keyboard, and joystick and so on.
  • The input unit helps to convert the inputted instructions into machine-readable (0’s and 1’s) for later processing.
  • The Input Unit transfers the data to primary memory of computer system.

Central Processing Unit

CPU (Central Processing Unit), you  can say it the “Brain” or “Heart” of the computer system. CPU is a hardware electronic device that is capable to perform various types of operations like as arithmetic and logical operation. It has ability to perform all calculations, comparisons or operations inside of the CPU.

CPU functions are

  • Fetch all instructions from memory
  • Handle the sequence of all instruction
  • To make communication in between all peripheral devices
  • Handle the flow of all data and instructions from one component to other.
  • To able to perform computation needed as per the application program.

Central Processing Unit has two segments like as arithmetic logic unit and control unit.

Arithmetic and Logic Unit

ALU (Arithmetic logic unit) has responsible to perform all arithmetic and logic operations, and data inserts via input devices, then going to store in the main memory storage unit.

Arithmetical Unit can handle few simple operations like as addition, subtraction, division, and   multiplication.

Logical Unit is capable to control the logical operations like as AND, OR, EQUAL, GREATER THAN, and LESS THAN, and so on.

Other operations like as comparing, selecting, matching, and merging data also performed by Logical Unit.

Logical Unit is also able to perform Bit-shifting operations like as left shift is representing by the << operator and the right shift is represented by the >> operator.

Control Unit

The control unit (CU) deals to perform all activities and operations of computer inside the CPU. Control unit has a responsible to control input/output, memory, and other devices which linked to CPU.

Control unit obtains the set of instructions or information, then it helps to convert the instruction set to control signals, then these signals will move to central processor for later processing. CU is able to understand which types of operations to execute with accurately.

The control signals are getting to help as per the prioritizing and scheduling the activates. It allows to make coordination all task inside computer in syn along with input and output units.

Control Unit Functions are

It gives to instruct the input unit, where to save data, when input unit obtains it from the user through few input devices.

Control unit can read one instruction at a time while executing of a program, and then it helps to execute all instruction at the ALU.

The output of execution ALU delivers after the calculation is hand over to control unit that direct it move to memory and also to output unit for seeing the output on the screen.

Memory Unit

Memory unit also plays the major role in the computer system because it helps to store data and instructions before and after processing. This unit transfers the set of instructions to another unit of system as per the need.

Memory Unit is divided into two categories like as –

Primary Memory:  Primary memory has other names the “Main Memory” or “Internal Memory” or “Primary Storage Device” or “Internal Storage Device.” They play vital role in computer, because those memories are capable to access all data directly from CPU with the help of various buses.

These memories have less capacity for storage and made by integrated circuits (IC) or semiconductor components.

Types of Primary Memory

Register: Registers are enabling in the CPU. They have low capacity for storing the instructions, and data only on before and after processing mode.

Cache Memory: This cache memory has higher speed for accessing data, and allows to computer for storing piece of data in temporary nature. Cache memory is place at near the CPU and RAM. This memory speed is very fast because its travel distance is short between RAM to Cache memory. There are three types of Cache memory such as – Level 1 cache, Level 2 cache, Level 3 cache.

RAM: RAM is primary memory and RAM stands for “Random Access Memory“. Ram is capable to access any data randomly any time as well as from any location to computer. This is volatile storage memory means to temporary memory in nature, because entire data goes delete while computer get turn off mode. RAM regains all data from CPU in run-time and sends to control unit, and it is a fastest memory to hard disk.

RAM Types are:

Static RAM: Static RAM is also volatile primary memory, and it made by flip-flop. Static Ram works in computer as a form of Cache Memory, but it consumes more power as well as more costly to DRAM. In Static RAM uses six transistors, and each transistor use for one bit.

Dynamic RAM: Dynamic RAM is other types of RAM, and volatile also in nature. In which use the capacitors for storing data in few milliseconds when power turn on. Dynamic RAM has slow speed as well as consume low power but has capable to store more data compare to SRAM. 


ROM is primary memory and ROM stands for “Read Only Memory”. This memory is able to store data in permanently means to have non-volatile in nature. ROM is programmable chip because in which stored all instructions that are most required when to start computer. ROM has not limitations for computer because these chips use in other equipment like as washing machine and microwave as well.

There are four types of ROM such as:

MROM: MROM stands for “Masked ROM“.  MROM has to contain the all pre-planned programs like as piece of instructions, and cheaper as well.

PROM: PROM Stands for “Programmable Read Only Memory“. Users can store any data as per their requirement because these ROM is available in market in blank. But in which store instructions (programs) only one time because after filling programs it cannot delete.

EPROM: EPROM Stands for “Erasable and Programmable“. In these types of ROM, users have power to editing (erase) the stored instruction (program) in EPROM. EPROM is erasable by ultra-violet light for some time like as 40 minutes.

EEPROM: EEPROM Stands for “Electrically Erasable and Programmable Read Only Memory“. In EEPROM, all activities such as programming and erasing will perform as electrically. This EEPROM is able to reprogrammed and erased in more than ten thousand time. 

Secondary Memory: Secondary storage devices are volatile in nature, it means that data does not discard while power turn-off, in which all data store for long time. Secondary memory has the speed of access of data is very slow compared to primary memory, and cheaper as well. 

Types of Secondary Memory

There are four types of secondary memory; below shown all, you can check them!

Magnetic Storage Devices: Magnetic storage devices store all data by using magnetized medium, and those types of data saved in that medium in the binary form like as 0 and 1. This magnetic storage has also non-volatile storage nature.

Today’s, mostly people are preferring to magnetic medium, because on the magnetic storage devices can be performed read/write activities very easily. Magnetic storage devices have huge capacities for storing data that it’s more attractive point.

These storage devices are not more costly but their data accessing power is slow, but this magnetic mechanism also to be used in the RAM that have good data accessing power to other.

Optical Storage Devices: In the optical storage devices, all read and write activities will perform by light. All recording information stores at an optical disk. As per the opinions of data scientist that compact space is most useful for huge data storage.

Their big advantages are not more costly, light weight, and easy to transport because it is removable device unlike hard drive.

Flash Memory Devices: Flash Memory was introduced by Dr. Fujio Masuoka in 1980. Flash memory is also known as electronically erasable programmable read only memory (EEPROM), because in which piece of  code like as programming can be write and erased by electrically.

This memory also uses for the storing data to computers as well as electronic devices such as USB flash drives, MP3 players, digital cameras and solid-state drives. Flash memory is non-volatile in nature because all data are persisted in the memory when power is turn-off.

Online Cloud System: Clouding is systematically model for storing data in computer, and in which entire data are stored in logically nature. Those clouding system are managed by other hosting companies.

With the help of online clouding, all data can be access by couples of users anytime and anywhere. Big advantages are not place limitation as well as no need carry any storage device.

Output Unit

The output unit of the computer system delivers the results of computation and displaying the output outside the world. The output unit generally works as the opposite process of the input unit and it convert the binary language digitalized information to electronic impulses, which are readable to the output devices. There are few output devices, which are commonly used like as monitor, projector, headphone, speaker, etc.

Output unit provides the result into two forms like as soft copy or hard copy. The monitor is used for soft copy as displaying on the screen, whereas printer is used for hard copy as displaying on the paper.

Output Unit Functions are

  • Output Unit receives the data or information into machine language from the primary memory of computer system.
  • Output Unit helps to convert the machine language into human – understandable.

Difference between Digital Systems and Digital Computer


Digital Systems

Digital Computers

Representation of Data

Digital systems represent data using discrete values or states, such as 0s and 1s.Digital computers also represent data using discrete values or states, such as 0s and 1s.


Digital systems are designed to store, process, and communicate information in digital form. They are found in a wide range of applications, including process control, communication systems, and consumer productsDigital computers are machines that employ a binary number system and perform various computational tasks. They consist of hardware and software components.


Examples of digital systems include digital watches, digital cameras, and digital audio players.Digital computer’s examples include personal computers, laptops, and mainframe computers.


Used in several applications, including signal processing, communication, and data storage.Used for numerical computations, control applications, and data processing.


Digital systems may consist of various components, including logic gates, flip-flops, and microcontrollers.Digital computers consist of hardware components such as the central processing unit (CPU), memory, and input/output (I/O) devices, as well as software components such as the operating system and application programs.

FAQs (Frequently Asked Questions)

What is digital computer with example?

The digital computer can be defined as digital systems that are able to get process information at the higher speed. Digital computer receives the input data that it can process and finally converts the output data; and send it to the output devices for displaying at the front of you, for example of digital computers are smartphone, PDA, Tablet, PC, and etc.

What is digital computer and digital system?

Digital computers are also known as the ‘Digital System’ because they are able to perform several computational tasks with in less time duration. The first digital computer was developed by John Vincent Atanasoff in 1940s; and Clifford E.Berry one of their students was helping for inventing.

What are the components of a digital computer?

A digital computer has four basic functional unit like as (1) input-output equipment, (2) main memory, (3) control unit, and (4) arithmetic-logic unit. Each one is explained above in this article; you can check them.

What is digital computer and explain the function of each block?

Through this article, already we have been explained about all blocks of digital computer in detail, you can read them.

The Bottom Lines

Through this article, you have been fully educated about what is digital computer; as well as block diagram of digital computer with its components and their functions with ease. If this article is valuable for you, then please share it along with your friends, family members or relatives over social media platforms like as Facebook, Instagram, Linked In, Twitter, and more.

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Happy Learning!! 

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