Stepper Bipolar circut: http://arduino.cc/en/Reference/StepperBipolarCircuit
I have this bipolar stepper motor "Stepper motor - 200 steps/rev, 12V 350mA - " which i am connecting to an Arduino. The ardunio as i understand can only deliver 5 volts of power, so its not enought for the stepper. Based on this circut, what kind of power supply do i need to power the motor? Can i just connect the GND of the h-bridge and NPN transistors to a 12v ordninary house hold battery? What is the difference in having an external power supply and just connecting a ordinary battery directly?