Power Supplys Attempt (2)

[Webb]

The max232 IC, a simple rs232 interface chip, has negative voltage
outputs. This is used on an embedded controller board I use to satisfy
the need for negative voltage (low current) by the A/D. 

You'd be well served, I think, to stick to a heavily filtered, isolated,
and regulated +5V then derive the other voltages with DC to DC. The evil
electrical environment in an auto is not to be underestimated.

RTW

FJB203 at aol.com wrote:
 
> In a message dated 97-04-08 12:09:51 EDT, you write:
> 
> > Depending on what you want to run with the PC, you'll only need 5V.  The
> >  other voltages are for the floppy and hard drive.  But if you were to use
> a
> >  flash drive instead of a floppy and hard drive you could get away with
> only
> >  a 5V supply.
> 
> Don't need a floppy, do need a HD <G>, but I need the negative voltages for
> the A/D card I have, unfortunately.  I tried removing the negative leads to
> the power supply, creating a "good power" signal, and the pc worked fine with
> only the +5 +12 volt lines, however the A/D card, when inserted, wasn't even
> remotely stable, even when measuring 0 to +12V only signals, such as in a
> card.
> 
> >  By the way there was a big discussion on this subject a few months back,
> >  check the archives and you should find lots of useful info.
> 
> Will do Dan, probably better than filling up an EFI mailing list with PC
> power supply issues :)
> 
> Thansk!
> 
> Fred