Hello!
I am a noob in all this arduino stuff, since I only became interested in the last few days.
After searching and searching the net for days, I still have one doubt regarding powering motors and motor shields.
I have one motor shield connected to two 5V stepper motors and I want to power them.
Would it be okay to use a 12V 1A wall wart?
I really don't know how to determine the required voltage and current for these things 
I would be much obliged if someone could help me.
Thanks!
A 1 amp power supply could run two motors so long as they only draw 1/2 amp each. Find the amp draw of your motors at stall. Times that by two and it should be a reasonable place to start.
Alright, thank you!
the motor is the 28YBJ-48 Stepper Motor, and the current draw is about 250mA when stopped and 200mA when at full speed. So 250*2=500mA
Maybe 1A it's a little too much
1 amp power supply should be good. It's not like the power supply forces the amps at the motor. The motor has to be able to have the amps it needs to run right. A power supply operating at a higher voltage like 24v would be a problem.
Awesome, I was confused because I didn't have any reference but now I understand.
Thank you for your help!
I just book marked this for myself, it does not cover power supplies per say but should have useful info:Stepper Motor Basics - Motors, Mechanics, Power and CNC - Arduino Forum