Wagner Lipnharski wrote:

> Bipolar / Unipolar:
> -------------------
> The Unipolar motors *requires* a floating connection, in a "H" bridge
> style, so a coil current switch flow direction for different magnetic
> field polarity.

> *Any* bipolar motor can be used as Unipolar (center tap goes floating,
> no connected), what increases its torque, but requires bipolar coil
> voltage doubled at VCC (two coils in series now). So, a bipolar motor
> for 6Vdc, when connected in a H bridge and used as unipolar requires
> 12Vdc at the top of the bridge.

  The *problem* is, Wagner, that your definition of bipolar/ unipolar is
the *opposite* of Jones' article:
  http://www.cs.uiowa.edu/~jones/step/circuits.html
--
  Cheers,
        Paul B.