Steppermotor 2amp + ULN2003 = fry

I just tried to connect a 2 Amp stepper motor to ULN2003, and yes, it did fry. Any suggestions on other chips that might handle this amount of current? And info about wiring also.

I´m also worried that I blew my motor. Do you have any easy and fast tips on how to chech if it is dead?


By the way, it is this motor:

have you read this post:

I guess I would use something like a TIP41A (transistor) instead of the ULN2003. But I did not look into the motor specs, maybe the ULN2003 is ok but you wiring was wrong? If you post the schematics we can check it.

To check out the motor I would think that a ohm meter check to make sure all the windings still have continuity (good) and a check to see if there is any continuity between windings and the motor case (bad).


I have to admit that I lack some basic knowledge about electronics. I am doing Fine Arts and this is something I need for an exhibition in two weeks, so I am very stressed out that it does not work. Any help would be highly appreciated! I am sending you my setup. I tested this same setup with a smaller motor (about 0,5A I think- 6 wires, not 8 like my new one) and it worked. But with the new motor with 8 wires it worked for about 5 seconds, then it slowly stopped. ANd now the old one does not work eighter, so the ULN2003 is fried I think. I also read the specs of the ULN and it said 0,5A max load.

So does anyone know of a different setup that can deal with my 2amp motor?

Thanks alot!

I also read the specs of the ULN and it said 0,5A max load

BUT that is only maximum current of one channel. It is the heat dissipation that limits the whole chip to a maximum of only 650mA. See:-
and the power examples page as well.

As for driving stepping motors see:-

Thanks for that.

Could someone give me some practical tips on how to solve this problem? Is my wiring correct and why did it stop working? Do I need an power adapter that supplys exactly 2A, or is it ok if it can supply like 7A?

Sorry, I am in kind of a desperate situatiuon here.


Do I need an power adapter that supplys exactly 2A, or is it ok if it can supply like 7A?

You need a power supply that can supply at least 2A, so a 7A rated one would be bigger than you need, but would work fine. Remember that a power supply will only supply as much current as the load demands, and in your case the demand is 2A.

you say:

The simplest way to do this is to use four VMOS power FETs, most N-channel FETs are suitable.

and in figure III a VN10KM is used. Isn’t this a FET with only 310mA continuous drain current? Will this be sufficient for the 2A motor? I suggested to use a TIP41A, will this do the job? So might he use four TIP41A?

And I guess 2A at 12V will produce some heat if you run it for a few minutes…

Isn't this a FET with only 310mA continuous drain current?

No it has a continuous current of 1A so it won't be suitable for your motor.

The TIP41A is a transistor not a FET. Yes it will do but you have to:- 1) Put a current limiting resistor in the base. 2) It only has a minimum gain of 15 so for 2A you will need a base current of 133mA - This is more than an Arduino can supply so you would be better using another transistor with it to give a Darlington pair. 3) The Vsat is 1.5V so it is going to dissipate 1.5 * 2 = 3 Watts so it is going to need to be on a heat sink.

You would be better going for a bigger FET.

Thank you very much, did not recognize the minimum gain. Of course 133mA is too much and building a Darlington pair is not a good solution, so I suggest, it would be best to find a suitable FET.

Can you name a FET for this application that fits? I guess that is what snaske is looking for.

How about a SPP04N80C3 It has a gate turn on of 3.9V max It has a whopping voltage and big current:-

good advice, I will order some samples of this FET.

Maybe this is off-topic, but would it also be possible to use a n-channel IGBT like the HGTG20N60B3D ? datasheet:

I have never worked with IGBTs, can they be used with 2A DC motors or stepper motors?

Just looked at the data sheet and see that you need 6V to turn them on in all cases. This is a bit too high for direct drive from an Arduino so you would need to drive it with a transistor first. I know it says the minimum turn on is 3V but that is not a guaranteed turn on, to do that you need 6V.

thank you again. The point about 6V was not clear to me (because of the 3V min.) but if you say that a safe on will need 6V then I will not try this part.

Yes data sheets are difficult to read especially for beginners. There is a spread in a lot of parameters in devices. With this turn on voltage you have to insure that you are above 6V to fully turn it on and that you are below 3V to turn it off. In practice for any one device there will not be such a range but there is no guarantee where the turn on and off points will be. Therefore the manufacturers give a range which they do guarantee all devices to be within. This means when you design things you always have to take into account the worst case so that your design is repeatable. You could use these transistors and it would work perfectly with the Arduino, but the next person to try it would have difficulty, it would be a bad design. And there are enough of those on the internet already. ;)

Data sheets are a problem for the newcomer! Remember that they're written for experienced engineers, and not intended as tutorials. They're also a form of contract between the chip maker and the chip user, so they do become almost legal-ese sometimes.

For a more tutorial approach, you can sometimes find Application Notes from manufacturers. These documents are much more like a cookbook of useful circuits and circuit ideas. There's a good one from National Semiconductor on comparators:

Note that the document number begins with "AN", which is a good sign.

Here are some Application Notes from International Rectifier, which include a few on IGBTs:

(scroll down a bit for the IGBT stuff)

Thanks for the link to the IGBTs. Never worked with them and just wondered if they are good for the problem discussed here.

And of course one should read the datasheet more careful than I did in this thread - novice or expert.

Maybe snaske can post what the solution is that he will use and maybe post the final schematics.