I am a beginner at Arduino. I want to power the Arduino through the USB cable that is usually plugged in the USB of the laptop, but plugged in the wall instead of the laptop.

Here are my questions:

  • Can I use a phone charger that has a USB (in which the end of the USB cable will go instead of the USB of the PC)?

  • What should I look for written on the charger so it is best compatible?

  • Is it ok to be done that way?

  • Will it be the same as means of power like when it is plugged in the PC (for example when later on I connect LCD display, diodes, etc.)?

I did my research, but it got confusing, so I wanted to ask my own question. Thanks in advance.

2 Answers 2


Yes, you can power the Arduino using a USB phone charger.

The Arduino Uno draws less than 100mA when connected by itself. So ideally you would want the USB phone charger to provide at least 100mA. All of the USB chargers I have come across to date provide more than 400mA. Most of the modern USB chargers provide upwards of 1A for fast charging of your phone.

A USB(2) port of a laptop can provide up to 700mA to the Arduino (500mA continuous).

In terms of the overall current draw, it really depends on what you have connected to the Arduino. LEDs generally draw 20mA or less per LED. Some screens can draw anything from <100mA to a couple of amps. Most of the screens I have come across draw less than 1A. It really depends on the devices you want to connect.

For the most part, a USB charger will be sufficient.


As you are still a beginner so I would not go into complex details. Your Arduino can run perfectly on a laptop powered USB but try to avoid connecting the power hungry electronics with your Arduino while powering it from the laptop USB port.

A Laptop USB port can give nearly 700mA that is enough for Arduino to run a couple of sensors easily.

Secondly, most wall chargers give 1A(1000mA) current that is better in my opinion. It can handle some power hungry electronics better then connecting your Arduino with the Laptop USB port.

I personally power my Arduino with either a Wall Charger or a power bank. Hope it helped solve your problem.

The more you dig into Arduino, the more fun it becomes. So have fun and be Creative.

  • How many V should the charger be? 5V or 12V? @M. Hussnain
    – the.matrix
    Commented Feb 24, 2017 at 7:17
  • He doesn't really have to worry about blowing up his USB port on the laptop, the arduino board has a 500mA poly fuse on the USB power in line so it should blow before his laptop USB gets damaged. You can't draw more than 500mA from USB, you can only draw about 1A from the barrel power jack, although it's the absolute maximum as the voltage regulator will get very hot very quickly. @the.matrix the barrel jack must have more than 7 volts to get 5V out of it, but try to keep it as close to 7V, 9V is fine, 12V is meh. The bigger the voltage difference (Vin - 5), the hotter it will get. Commented Feb 24, 2017 at 10:01
  • And how many volts should a charger that goes into the USB be @Andrei Dragan ?
    – the.matrix
    Commented Feb 24, 2017 at 12:28
  • The USB voltage is 5V. Commented Feb 24, 2017 at 13:07
  • The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins on Arduino bypasses the regulator, and can damage your board. Commented Feb 24, 2017 at 13:11

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