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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?

  • 3
    \$\begingroup\$ A small but important nitpick: Power is measured in watts and no device can provide 5 V of power! In DC world, power is current multiplied by voltage. There are quite a few motors that will run fine on 5 V, but will require lots of current which could be a problem for Arduino. So the point of this comment is: It's a good idea to use external power supply even if you use a 5 V motor with Arduino (or similar microcontroller platforms that aren't designed specifically for motor control). \$\endgroup\$
    – AndrejaKo
    Commented Feb 2, 2013 at 21:49

1 Answer 1


If you wanted to use the battery, the positive terminal of the battery would connect to the "V2" pin of the L93D and the negative terminal would be connected to your common ground. The "1in" and "4inn" pin would be connected to your Arduino I/Os.

You could also use a DC-DC boost converter taking the 5V input and outputting 12V.


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