Path: utzoo!attcan!uunet!cs.utexas.edu!samsung!usc!apple!genbank!ames!amdahl!pacbell!sorinc!magik
From: magik@sorinc.PacBell.COM (Darrin A. Hyrup)
Newsgroups: comp.sys.amiga
Subject: Re: Can You Use A 2000 24 Hours A Day?
Summary: Sorry for the bad analogy.
Message-ID: <8911250912.AA07846@sorinc.PacBell.COM>
Date: 25 Nov 89 10:12:35 GMT
References: <24043@cup.portal.com> <6113@shlump.nac.dec.com> <8911152235.AA07854@sorinc.PacBell.COM> <1149@becker.UUCP>
Followup-To: comp.sys.amiga
Organization: Yes, I'd like that.
Lines: 48

In article <1149@becker.UUCP> bdb@becker.UUCP (Bruce Becker) writes:
>In article <8911152235.AA07854@sorinc.PacBell.COM> magik@sorinc.PacBell.COM (Darrin A. Hyrup) writes:
>|[...]
>|the power-up phase. This is why lights usually burn out when you turn them
>|on, rather than burn out while they are going.)
>
>	 Although the advice about wear and tear is OK
>	 as far as it goes, I really must object to the
>	 explanation given in the example. The reason
>	 a light bulb burns out when you turn it on is
>	 due to the fact that Tungsten has a high positive
>	 coefficient of electrical resistance with respect
>	 to temperature. When the lamp filament is cold,
>	 it has a very low resistance, so many more electrons
>	 per second rush through it, producing a surge
>	 which, when the filament is weakened from much use,
>	 will eventually zap it.

Sorry about that. It sounds like you are much more knowledgeable in this
subject than I. The analogy given was the one given to me in first year
electronics in school years ago, and although I know there is more to it
than the simple definition I gave, it does help to illustrate the principle
of current surge leading to possible equipment failure even if it isn't
exactly correct.

>	 Power supplies for electronic devices also exhibit
>	 a current surge on startup due to the need to
>	 charge up the smoothing capacitors on the output.
>	 Switching power supplies are much less susceptible
>	 to this surge due to the smaller size of the filter
>	 required, but they are more susceptible to voltage
>	 transients on the AC line, which might or might not
>	 be associated with startup.

Also very true. Its always best to run an AC regulator on the computer's
power anyway to help protect against power fluctuations. In most cases
they are pricey, but I have seen surge suppressors that include voltage
regulators as well, which would make a good investment for computer owners.

>Cheers,
>   ^^	  Bruce Becker	 Toronto, Ont.

Again, sorry for the misleading analogy.
--
Darrin A. Hyrup 	     // AMIGA Enthusiast	 rencon!esfenn!dah
magik@sorinc.PacBell.COM   \X/ & Software Developer   pacbell!sorinc!magik
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"Speak little and well, if you wish to be considered as possessing merit."