Spehro,

I am not using 12V anywhere in the circuit.  I have 5v/1A rated
stepper motors.  If you look at my schematic again
(http://www.excelsus.com/~remy/DualStepperSchematic.pdf) you will
notice that the supply is at +5V on the motors.  Actually, the entire
board, logic AND motors, is powered off the same power supply bus.
I am sorry for the confusion, as I know the folks at DAK engineering
were using 12V in their stepper circuit.

I put the zener in there because I didn't know any better, and it was
suggested on that other site.  I am thinking I'll just use a regular
diode now.  Again, everything is at +5v and gnd.

Thanks for all the assistance.  I am getting together the hardware
the steppers will move about.  Project alpha is a CNC router table
for my Dremel tool or drill press.  Project beta is a robotic tape
handler for my linux box.  My final goal is a robotic CD changer
for my home stereo.  Sure, I could put all of my CD's on hard drives,
even in PCM (i.e. wav) format, but that's boring.  It's much cooler to
have a robot that moves the discs from a largish rack and puts them
in the player, and then returns the discs to the rack when done.
Oh, women will be flocking all over me (not).

Have a good one,

Gustaf

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Spehro Pefhany
> Sent: Saturday, February 28, 2004 11:35 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE:] Release of magic smoke
>
>
> At 11:21 PM 2/28/2004 -0500, you wrote:
>
>
> >Cathode of the zener to pin 9, anode to ground (or +12 is better,
>                           ^^^^^
> Should read pin 10.
>
>
> >actually, provided the zener voltage isn't too high). You could just
> >connect pin 8 to 12V, but that would reduce the performance of the
>        ^^^^^^^^
> pin 10.
>
> I think I'll quit now, not used to this much beer anymore. I'm also
> working on a design with the ULN2003A driver..
>
> Best regards,
>
> Spehro Pefhany --"it's the network..."            "The Journey is
> the reward"
> speff@interlog.com             Info for manufacturers:
http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

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