Arduino Masterclass - Lesson 2: Circuit Components
Explore the Arduino Uno and its components in 3D
ℹ️About Arduino Uno Versions
The Arduino Uno has gone through several revisions over the years, each bringing improvements and updates. While there are multiple versions available, the Arduino Uno R3 (Revision 3) is by far the most popular and widely used version.
Why is the R3 so popular?
- ✓Most tutorials and projects are based on R3
- ✓Excellent compatibility with shields and accessories
- ✓Stable, proven design with years of community support
- ✓Easy to find and purchase from many retailers
💡 The 3D model shown below represents the Arduino Uno R3, which features the ATmega328P microcontroller and is the standard reference for most Arduino beginners.
💡 No Need to Memorize Everything!
This page is meant as a handy reference guide—you don't need to memorize all these details right now! Feel free to bookmark it, share it with friends, or come back whenever you need to look up Arduino pin functions and specifications. It's here to help you whenever you need it.
Component Reference
D0-D13 Pin (PWM Pin ~): 3,5,6,9,10,11
14 digital I/O pins for reading sensors and controlling outputs. Pins 3,5,6,9,10,11 support PWM (~).
A0-A5 Analog Input
6 analog input pins (A0-A5) for reading analog sensors with 10-bit resolution (0-1023).
Power: 5V, 3.3V, GND, Vin
Power supply pins: 5V (regulated), 3.3V (regulated), GND (ground), and Vin (external power input 7-12V).
ATMEGA328 Microcontroller
The main chip that executes your code. 32KB flash memory, 2KB SRAM, 16MHz clock speed.
USB/Type-C Connector
Connects to computer for programming and power. Provides 5V power and serial communication.
External Power Supply
External power input jack. Accepts 7-12V DC power (9V recommended) for standalone operation.
Reset Button
Restarts the program from the beginning. Useful for debugging and testing your code.
16MHz Crystal Oscillator
16MHz crystal provides precise timing for the microcontroller's clock signal.
5V Voltage Regulator
Converts external power (7-12V) to stable 5V for the board and components.
Polyfuse (Overcurrent Protection)
Resettable fuse that protects against overcurrent. Automatically resets when current returns to normal.
ICSP Header (ATMEGA328)
In-Circuit Serial Programming header for advanced programming and bootloader updates.
Arduino Uno PCB Board
The main circuit board that holds all components and provides electrical connections.