“what kind of DC adapter can I use to power my Arduino?”
“The short answer is: 9 to 12V DC, 250mA or more, 2.1mm plug,
“The long answer is that an off-the shelf Arduino adapter:”
- must be a DC adapter (i.e. it has to put out DC, not AC);
- should be between 9V and 12V DC (see note below);
- must be rated for a minimum of 250mA current output, although you will likely want something more like 500mA or 1A output, as it gives you the current necessary to power a servo or twenty LEDs if you want to.
- must have a 2.1mm power plug on the Arduino end, and
- the plug must be “centre positive”, that is, the middle pin of the plug has to be the + connection.
Source : Arduino Site https://playground.arduino.cc/Learning/WhatAdapter/
You can easily get plenty of power adaptors for Arduino in the Shop or Junk shelf at ITP. But You might need to aware of the polarity of the power supply.
As you can see the above picture, the power supply for Arduino has to be positive inside (Center- positive(+)), and negative outer side of (Outer- Negative(-))the jack.
There are a few adaptors are not the same polarity of this, and it won’t work with your Arduino.
To sum up,
- Using USB (AB cable) to supply for Arduino. (I often used
Iphonecharger with an A/B cable)
- Using a
9-12Vpower supply with Arduino power jack.