> -----Original Message-----
> From: Pic Dude [SMTP:picdude@PILOTTOOLS.COM]
> Sent: Friday, August 30, 2002 3:14 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [EE]:  Why does a PC need 12V?
>
> I need to build a power-supply to run a PC in a car, so I'm
> trying to figure out why I really need +/- 12V, which may be
> tough to produce with the ignition off (not enough overhead
> for the regulator).  I could build a DC-to-DC coverter that
> would raise the voltage, but that means $$$.
>
Some modern motherboards (notably P4 boards) use the 12v supply to derive
the high current CPU core voltages, but this is unlikely on an older system.
12v is used for serial comms, BIOS programming voltage and some sound cards
use it.

Regards

Mike

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