The regular Arduino primarily operates at 5V. While it can accept a higher input voltage like 12V, its internal working voltage and input/output signal levels are typically 5V.
Understanding the voltage specifics of your Arduino board is crucial for powering it correctly and connecting sensors and other components safely.
Arduino Operating Voltage vs. Input Voltage
Based on the provided information:
- Operating Voltage: The core of the regular Arduino "works" at 5V. This is the voltage at which the microcontroller operates. (Note: some versions run at 3.3V, but the reference specifically mentions the 5V case first).
- Input Voltage: The board can accept a higher voltage, such as 12V, through its barrel jack connector.
- Voltage Regulation: This higher input voltage (like 12V) is regulated down to 5V by an onboard voltage regulator before it powers the microcontroller and other 5V components.
- Input/Output (I/O) Voltage Levels: The digital signal levels on the Arduino pins are also 5V. A logic-high signal is approximately 5V, and a logic-low signal is approximately 0V.
Why This Distinction Matters
Knowing the difference between the acceptable input voltage and the operating/I/O voltage is vital for:
- Powering the Board: You can safely power many Arduino boards with a 12V adapter through the barrel jack because of the built-in regulator. However, the board itself runs on 5V.
- Connecting Components: You must connect components that operate at 5V to the Arduino's I/O pins.
- Sensor Compatibility: You cannot feed 12V directly from a sensor into an Arduino input pin, as the reference states. Doing so can damage the microcontroller, which expects a maximum of around 5V on its input pins. If you need to interface with 12V signals, you would require voltage-level shifting circuitry.
Voltage Summary Table
Here's a quick summary based on the information:
| Aspect | Typical Voltage (Regular Arduino) | Notes |
|---|---|---|
| Operating Core | 5V (or 3.3V on some variants) | The voltage the microcontroller runs on. |
| I/O Signal Level | 5V | Logic High is ~5V, Logic Low is ~0V. |
| Input (Barrel Jack) | Can accept up to 12V or higher | Regulated down to 5V onboard. |
| Sensor Input Limit | 5V Max | Do NOT feed 12V directly into inputs. |
In conclusion, while a regular Arduino board can accept a higher voltage like 12V as input power, it fundamentally works at 5V, and its communication (input/output) happens at the 5V logic level.
