Can We Power Arduino Nano Through 5V Pin
Yes, Arduino Nano can be powered up through the 5V pin. The 5V pin in the Arduino has dual functionality. This pin can output constant 5V as well as act as power source when no external supply is connected against the USB port or VIN pin. It is typically used to power the Nano from an external power source, such as a DC power adapter or a battery. The 5V pin can supply a maximum current of 500mA.
Note: It is important to note that the 5V pin is not intended to be used as a primary power source for the Arduino Nano. It is intended for use as a power output to supply power to other devices or circuits and is not designed to provide enough current to power the Nano itself. To power the Nano, you should use the VIN pin or the USB port.
Following is the current limit of Arduino Nano board 5V pin:
| Board | 5V Pin Output Current | 3V3 Pin Output Current |
| Arduino Nano | 0.8A | 0.15A |
Warning: It’s not recommended to use 5V as input power source for Arduino Nano. As the 5V pin is connected to the output of the voltage regulator (LM1117) which means a slight increase in voltage will damage the Arduino Nano permanently.
Suppose voltage at output of regulator becomes higher than input which will result in large current flow from output to input resulting in damaging the board permanently. While powering Arduino Nano using the 5V pin always uses the regulated 5V supply.
LM1117 voltage specifications:
| Voltage Regulator | Output Voltage | Max Input Voltage | Max Output Current |
| LM1117 | 5V | 20V | 800mA |
Arduino Nano Power Sources
Arduino Nano has different power options. Having multiple power sources increases Arduino working and compatibility. To power Arduino Nano following ways can be used:
1: USB Mini Cable
USB mini port is the most reliable and efficient way of powering Arduino Nano as it provides us with constant 5V which can be directly given to Arduino Nano microcontroller and other peripherals.
2: VIN Pin
VIN pin can also be used as a power source for Arduino Nano. VIN pin works dual way. This pin is connected to an onboard voltage regulator which means it can not only give us 5V but also can power Arduino Nano through external power supply. Maximum of 16V can be given to the VIN.
It’s recommended to not apply voltage greater than 12V at this pin because excess voltages will be lost as heat during conversion.
3: External regulated 5V
Last power source on the list is a 5V pin. This is by far the most complicated way to power a Nano board. This is because the 5V pin bypasses the LDO regulator and any slight increase in voltage will damage Arduino permanently. This happens usually because of reverse current flow from output to input of the LDO LM1117 regulator.
Arduino Nano Power Tree
Following image shows the Arduino Nano power distribution. VIN pin voltage is given to the on -board voltage regulator which then requires it and gives constant 5V to the onboard microcontroller board.
Powering Arduino Nano Using Arduino Uno through 5V Pin
Now we will power the Arduino Nano using the constant 5V coming from the Arduino Uno board. Connect the 5V Uno pin with the 5V pin of the Nano board. After that connect the GND pins of both boards together.
Schematic
Following is the schematic image of Arduino Nano powering using the 5V pin.
Hardware
In hardware we can see that the power LED of the Arduino Nano is turned on using the 5V coming from the Uno board.
Conclusion
Arduino Nano can be powered using the 5V pin. The 5V pin is a power output pin that is located on the Arduino Nano and is used to supply a regulated 5V voltage to other devices or circuits. However, we can also power Arduino using this pin but make sure to use the regulated 5V supply. For more detail of the 5V Arduino nano pin see detailed description in the article.
