Linux-Hams archive - May 1998: Re: Watchdog

Re: Watchdog

Geoff Blake (terhi.victor@logonet.com)
Mon, 4 May 1998 20:29:12 +0100 (BST)


On Mon, 4 May 1998, Duvall, Michael J. wrote:

> >As I said, almost nothing in a computer uses -12V. It was originally
> needed by
> >DRAM chips for bias, but DRAM has not worked this was for a decade.
> Now, the
> >only thing commonly tied to -12V is an RS-232 port that would probably
> work as
> >well in practice without it.
>
> You are right.. almost nothing.. Just the hard disk and CDROM drives.
> Some hard drive take 2.7 amps starting and about .7 running.

Oops, Mike, I think that you may be confusing the -ve and +ve 12V rails.
The standard 4 pin plugs used for disk drives carry +12V and +5V rails
and two ground returns.

I have never seen a drive _suitable for fitting in a PC_ using other than
+12V and +5V (except some very early 8" drives that used 115/230VAC and
24VDC, as well, but who in their right mind would use one of those in a PC
now!).

Geoff

-- 
     Geoff  Blake	   egsxst.zkffynfe@mari-el.ru	     linux 2.0.31
      Chelmsford	      wlbqm@nowanet.pl               i586
      Intel create faster processors - Microsoft create slower processes