Ergo, caveat emptor. The difference between unipolar and bipolar design is covered in this stepper motor overview by Monolithic Power. A unipolar stepper motor like the 28BYJ-48 has four phases ...

If you’ve been a good little hacker and have been tearing apart old printers like you’re supposed to, you’ve probably run across more than a few stepper ... motor as a more efficient bipolar ...