What power supply can I use with my Arduino board? – Arduino Help Center

All Arduino boards need electric power to function. A power supply is what is used to provide electric power to the boards and typically can be a battery, USB cable, DC power adapter or a regulated power source device.

There are different ways to power your Arduino board. The most common way is through the USB connector available on every board, but there are a few other possibilities to power your board. If you like to know more about this, the different ways to supply power to your board are listed below:

Note

Incorrect input voltage can damage your board. Never connect an external power supply before checking the input voltage limits. Look for technical specifications in Arduino Documentation.

1. USB

The most common way to power an Arduino is through the USB connector.

Voltage: 5V DC.
Source: Can be powered by a computer USB port, a USB wall adapter (like a phone charger), or a portable power bank.
Compatibility: Every Arduino board features a USB port for both programming and power.

2. DC Barrel Jack

Some Arduino boards (such as the Uno, Mega, and Due) feature a dedicated barrel jack for external power. This allows the board to operate independently of a computer.

Voltage: 7V to 12V DC is recommended.
Connector Type: 5.5mm cylindrical plug with a 2.1mm center pin hole.
Polarity: The adapter must be Center-Positive (the inside pin is positive, and the outside sleeve is negative/ground).

Make sure the power adapter complies with your Arduino board specifications.

If you find that additional power is required from your Arduino board to operate it properly, or if you need to operate the Arduino board disconnected from a USB port.

Important: While the adapter plugs into an AC wall outlet, it must be a DC Power Adapter that converts high-voltage AC into the low-voltage DC required by the board. Never connect AC voltage directly to the board.

3. Battery Socket (Li-Po)

Many modern and portable boards, such as the MKR family (excluding MKR FOX and WAN 1300), include a dedicated battery connector.

Voltage: 3.7V (standard for Lithium-ion Polymer batteries).
Connector Type: JST PHR-2.
Feature: These boards typically include a built-in charging circuit, allowing the battery to charge whenever the board is plugged into USB.

4. VIN Pin

The VIN pin allows you to power the board using a regulated power source or a battery pack by connecting directly to the board’s internal voltage regulator.

Connection: Connect the positive (+) wire to VIN and the negative (-) wire to GND.
Voltage: Check your specific board’s documentation for the allowed VIN range (usually 7-12V for boards like the Uno).
Warning: The VIN pin is an INPUT only. Never connect a power source here while also providing power through the Barrel Jack, as they are often connected to the same circuit.

5. Screw terminal (MKR FOX and WAN 1300)

These specific boards feature screw terminals designed for a 3V battery pack (usually 2x AA or AAA batteries).

Note: Ensure you respect the polarity (+/-) labeled on the board’s silk-screen.

Current Requirements (Amperage)

For most basic applications, a power supply capable of providing 1A (Ampere) is sufficient. However, you may need more current if your project includes:

Multiple Shields stacked on top of the board.
High-power components like motors, servos, or large LED strips. Total Current Calculation:

You should sum the current requirements of the Arduino board (roughly 50mA) plus the maximum draw of every component or Shield attached. Choose a power supply that meets or exceeds this total.

Tip: Using a power supply with a higher current capacity (e.g., a 2A supply for a 1A project) is perfectly safe; the board will only “draw” what it needs.

Thermal Limitations

The on-board 5V regulator handles the task of stepping down higher voltages (like 12V) to the 5V the chips need. This process generates heat.

To prevent the board from overheating, it is best to keep the total current draw from the on-board 5V pin below 800mA.
If your project requires significant power (e.g., several servos), use an external power supply for those components and connect the grounds (GND) of all power supplies together to ensure a common reference point.