I have bought DC power supply for LEDs some time ago. Its output is 12V, 1A DC. (Input:230VAC)
Arduino specifications says it can be powered by 7-12V, but I don't know if 1A is OK for it.
So, can I use my power supply to power up my Arduino UNO or Nano ?
If no, what should I look for? (I need to power up it from 230VAC)
Recommend at least 200 mA (USB supplies 500 mA) and anything over 1A is a waste unless you are using it to power the Arduino and some other 12V devices: the built-in regulator can't use more then 1A without overheating so even if the power supply can provide 1000A the Arduino will never use more than 1A at 5V.