Block Diagram of a Computer
- Siddharth Sharma
- Aug 13, 2025
- 2 min read
Updated: Aug 14, 2025
✅ What is a Block Diagram of a Computer?
A block diagram of a computer is a simple picture or drawing that shows the main parts (components) of a computer and how they are connected to each other. It helps us understand how a computer works.
✅ Main Components in the Block Diagram
There are five basic parts shown in a computer block diagram:
Input Unit
Central Processing Unit (CPU)
a) Control Unit (CU)
b) Arithmetic Logic Unit (ALU)
Memory Unit
Output Unit
Storage Unit (Sometimes shown separately)
📊 Block Diagram Structure
🔍 1. Input Unit
Used to give data and instructions to the computer.
Examples: Keyboard, Mouse, Scanner, Microphone.
Converts human language into machine language.
🔍 2. Central Processing Unit (CPU)
Also called the brain of the computer.
a) Control Unit (CU)
Manages and controls all computer operations.
Tells other parts of the computer what to do.
b) Arithmetic and Logic Unit (ALU)
Performs all mathematical (addition, subtraction) and logical (greater than, equal to) operations.
🔍 3. Memory Unit
Temporarily stores data and instructions.
Also stores results.
Two main types:
Primary Memory (RAM, ROM)
Secondary Memory (Hard Disk, SSD)
🔍 4. Output Unit
Displays the result of the processed data.
Converts machine language to human language.
Examples: Monitor, Printer, Speaker.
🔍 5. Storage Unit
Stores data and programs permanently.
Examples: Hard Disk, SSD, Pen Drive, CD/DVD.
✅ Flow of Data in a Computer
Input Unit – Data is entered
CPU + Memory – Data is processed
Output Unit – Result is displayed
Storage – Data is saved permanently
📌 Summary Table
Component | Function |
Input Unit | Takes input from user |
CPU | Processes data |
Memory Unit | Stores data temporarily |
Output Unit | Displays result to user |
Storage Unit | Stores data permanently |
🧠 Easy Way to Remember
IPO Model –
Input → Process → Output
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