View Full Version : Stepper motor control?

04-11-2010, 11:14 PM
Can I use some power transistors to control a stepper motor instead of using a darlington array? I don't have the uln2003, and I have a bunch of power transistors... I was thinking of having an I/O of the BS2 forward-biasing the transistors, with the collector connected to 6 volts and the emitter connected to the stepper motor pin. Would that work?

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PJ Allen
04-11-2010, 11:43 PM
You can configure discrete transistors as Darlington amplifiers and use them as you would the "gates" of an "array".

04-14-2010, 12:20 AM

The Darlington Array is a set of 8 transistors; so yes, you could use a bank of transistors to accomplish the same task.


Joshua Donelson
www.parallax.com (http://www.parallax.com)

05-01-2010, 12:14 AM
If you stepping motor is big and requires more current, use an NPN transistor i.e: 2N2222 or BC547 (coming from the outpot of the basic stamp) 1k at the base of the transistor, emitter to Gnd , 10k connected to collector to +12Vdc, then from the collector connect it to the gate of a MOSFET i.E IRFZ40, the source of the MOSFET to gnd and connect the drain to one coil of the stepper coils and from the other end of the coil to V+ typically +12 V parallel a diode to keep the MOSFET healthy, this configuration has to be repeated 4 times since the steppers usually have 4 coils. be careful that the transformer you are using is capable to supply the required current and voltage. These MOSFETS handle large inductive loads, you might need a muffin fan to keep your system cold and of course your MOSFETS have to have attached to a good heath sink.

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