David Drummond wrote in a message to Matt Mc_Carthy:

 DD> Al salaam a'alaykum Matt

 DD> 13 Dec 03 00:18, Matt Mc_Carthy wrote to WAYNE CHIRNSIDE:

 WC>>  When the heck is someone going to produce a standard ATX power 
 WC>> supply designed from the get go to be driven from either 120 AC or 12
 WC>>  volt deep discharge batteries?

 MM> They are _almost_ there.  The switching PSs can be run from DC, so 
 MM> just put 10 of those monster 12 volters together!  That should last a 
 MM> weekend or two...

 DD> How do you achieve the -12V? You'd have to set up your 12 volters
 DD> to produce 24V overall, with the centre tap as zero....

You'd achieve it by doing it the way they do it now.  With a transformer, 
and appropriate rectifiers and filtering and regulator...

There would be no difference on the output side -- it's only the input side
where things would be very different.

How much stuff uses that -12 anyway?

---