The power consumption of an Arduino Nano depends on several factors, but we can give you a solid range and the key things that affect it.
Quick Answer: The Short Version
For a typical Arduino Nano (with an ATmega328P chip) running a basic sketch like "Blink" without any components connected to its pins, you can expect:
- ~20 mA (0.02 A) at 5V when powered via the 5V pin.
- ~15 mA (0.015 A) at 3.3V when powered via the 3.3V pin.
However, this is just the "idle" consumption of the board itself. The real current draw comes from what you connect to it.
Detailed Breakdown
Let's look at where the power goes on a standard Arduino Nano (the common clone with an FT232RL USB chip).
1. The Microcontroller (ATmega328P)
This is the main brain. By itself, running at 16 MHz and 5V:
- Active Mode: ~5 - 10 mA
- Power-Down/Sleep Mode: Can drop to microamps (µA) with proper programming.
2. The Onboard Components
- Voltage Regulator (LDO): The Nano has a low-dropout regulator that provides 5V. It has a quiescent current (the current it uses just to operate) of a few milliamps.
- Power LED (the "ON" LED): This is often the biggest single consumer on the board! A typical LED with a standard 1kΩ resistor will draw about 3-5 mA.
-
USB-to-Serial Chip (e.g., FT232RL, CH340):
- FT232RL: Can draw 10-15 mA when active.
- CH340 (common in cheap clones): Can draw 15-25 mA or more.
Adding these up, the ~20 mA figure for the board alone makes perfect sense.
The Real Answer: It Depends on Your Project!
You must account for everything you connect to the Nano. The Nano itself is just the controller; the "workers" you attach consume most of the power.
Power Supply Recommendations
Based on the above, here's how to choose a power supply:
1. Absolute Minimum: 100 mA (0.1A)
This is safe for the board itself and a couple of small LEDs or sensors.
2. Recommended for Most Projects: 500 mA to 1A (0.5A - 1A)
This gives you plenty of headroom for servos, multiple LEDs, displays, and WiFi/Bluetooth modules without worrying about brownouts.
3. For Power-Hungry Projects (e.g., with motors): 2A or more
Crucial: Do not power motors through the Nano's 5V pin! Power them directly from your source and use the Nano only for control signals.
How to Power the Arduino Nano
You have three main options, all with different current capabilities:
1. USB Port (Mini-B/USB-B)
- Source: Computer USB port or USB wall adapter.
- Voltage: 5V
- Current: A computer USB 2.0 port provides 500 mA. A good wall adapter can provide 1A to 2.1A. This is the easiest and safest method for most projects.
2. VIN Pin
- Source: Unregulated DC power source (battery pack, wall wart).
- Voltage: 7V to 12V recommended (Absolute max 20V). The onboard regulator will step this down to 5V.
- Current: Limited only by your external power supply and the regulator's capability (see datasheet, typically ~800mA-1A max).
3. 5V Pin
- Source: A regulated 5V source (e.g., a stable battery pack or a dedicated 5V regulator).
- Warning: This bypasses the onboard voltage regulator. You must provide a clean, regulated 5V. Any voltage higher than 5.5V can permanently damage the board.
Summary Table
Final Advice: For any project more complex than blinking an LED, plan for a 500 mA (0.5A) power supply. It's a safe, common rating that will ensure your Nano runs reliably.
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