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From: ken@argus.UUCP (Kenneth Ng)
Newsgroups: sci.electronics
Subject: Re: PC Power ON/OFF Scheme
Message-ID: <1928@argus.UUCP>
Date: 13 Jul 90 18:22:40 GMT
References: <334@uncmed.med.unc.edu>
Distribution: usa
Organization: NJ Instit. of Tech: TEIES Project
Lines: 19

In article <334@uncmed.med.unc.edu>, uchuck@uncmed.med.unc.edu writes:
: Gentlemen,
: I have devised a scheme using a high current capacity relay and a couple
: of small control relays that will allow me to power up or down my PC
: system and peripherals simultaneously.  The design includes a power fault
: - no power back up feature so that the machine does not try to go through
: power up/down sequences that are not purposeful.  In addition, by the use

On a related note, a friend and I want to give our PC's the capability of
running off of batteries (similar to a UPS).  Rather than feed the 
battery current into an inverter that convert 12 VDC into 120 VAC, which
will feed the pc switcher that will convert the 120 VAC back into 12 and
5 volts, what would be the hazards of feeding +12, -12, and +5 directly
in place of the main PC power supply?  (Note: the original pc power supply
would be disconnected in this case.)  I remember back in the days of the
16K dynamic rams the -5 had to be turned on first.  Is there any such
restriction with pc equipment?  Obviously I plan to have voltage and 
current regulators, but is there anything else that is needed and/or
recommended?