You didn't reply to the *other* guy's comment on feeding the cats! Mark Willis wrote: > Makes sense - you can choose to always drive pairs of coils, though, > for higher torque. I can't see that. The coil which remains energized in this switchover contributes *nothing* to the torque except that by holding the armature *in between* positions, it reduces the flux coupling. This may give an extra repulsive kick at the start, but as it seems to me, less attraction at the end of the stroke where it is pulling *away* from the most-recently-energized pole. >> I'm sure you have *plenty* of spare plugs on the end of RD-BK-BK-YL >> leads! > "Never enough", despite the dozen spare power supplies in the garage It appears you, like me, can't bear to scrap equipment even when busted! > Given the 5 wires (instead of 6), I remembered all that, summat > vaguely but well enough as I've been watching the discussions in here. 5 and 6-wire units are almost identical, except that a 6-wire can be used as either a 5-wire or a 4iwire :-). >> A diode should be connected across each coil winding. The Anodes >> all connect to the Common wire, and the Cathodes connect to A B C >> and D. > AKA inductive kicks, yep. OK, makes sense. If we're getting particular here, the diodes do *not* go to the common, but to common via a Zener or resistor. >I need a known speed motor control to spin a little cylinder or disk > at a very high, controlled speed, for playing with a Nipkow heads-up > display design for wearable computers. Need something like a 30+ Hz > refresh rate for that, want some other motor then The complete assembly is available disposals from laser printer mechanisms. Including electronics, though that may be a challenge. The capstan assembly from a Hard Disk Drive is an alternative. And yes, if you have to go *buy* a stepper driver, the L293D is the way to go as it is created for the job. I'm miffed, they were available once disposals but snapped up before I could get my order in. -- Cheers, Paul B.