I'm not an electrical engineer, but I'm in the computer business and have
been exposed to UPS technology indirectly for many years, so I'll take
a stab at this with that caveat.
UPS stands for "uninterruptible power supply." Basically, it's batteries,
a power supply and an inverter in one box. The power supply converts AC
power to DC power to charge a battery and the battery supplies DC current
to the inverter, which in turn synthesizes an AC current--more or less--to
power your devices. At least, this is the "active" type UPS ... a "passive"
type just passes the AC current to your devices, charges the batteries, then
turns on the inverter when the AC supply falls below a certain level; i.e. you
The active type is preferred since there is truly no interruption of power to
your devices (since you're "running off the battery at all times"). The
cause a "blip" before the inverter cuts in totally, which may or may not cause
problem with your devices (might cause a computer to reboot). Cheaper UPSes
will produce AC output that is more like a square wave, better ones will
more of a sine wave.
Check this out:
Surge protectors come with different ratings ("joules" -- more is better).
some are rated for computers and some should only be used with power tools.
In addition, they do lose their effectiveness over time and should be replaced
This is informative:
Personally, unless you are really concerned about saving any documents you
are working on--and if you lose power a lot--I would buy top-notch surge
protectors. Or, buy a UPS for your computer and monitor and put DVD players,
TVs, etc. on good-quality surge protectors. UPS batteries will deteriorate over
time and need to be replaced (usually, it's cheaper to replace the UPS).
You now know more than the "ISC guy" at your wife's office ;)
Bob Spidell San Jose, CA firstname.lastname@example.org
'67 Austin-Healey 3000 '56 Austin-Healey 100M
Subject: ups (uninterrupted power supply) questions?
> just lost another answering machine, vcr and cable modem. I just got
> two new monitors and I'd hate to lose them, too. the i.s.c. guy at the
> wife's office recommended a u.p.s. as sort of un uber-surge protector,
> and it'd give me a chance to shut off the computer as well when the
> power went out. he's a nice guy and all, but I thought I'd ask anyway...
> will a u.p.s. (or at least do some kinds of them) function like a surge
> protector? is it worth using it as one? the only thing I'd use the
> extended power for is just to get to the computer to shut it down
> normally, otherwise everything else could go off whenever. but I would
> like maximum protection for the electronics, and those are spread all
> over the house. can I get one (large) u.p.s. and wire everything I want
> protected into it? am I better off just buying the best surge
> protectors I can find, and if so, how 'bout brand names and
> recommendations? so far I've lost four v.c.r.s, two answering machines,
> two d.v.d. players, and a cable modem. all but the modem were hooked
> into fairly new (less than two years old) protectors. and if you know
> of a cable protector, do tell. I'm told (by the cable co.) that you
> can't surge protect the co-ax because it will degrade the signal too
> much for the modem.
> and if I can use the u.p.s., any help with sizing, brands, etc.? I know
> wayyyy to little for the stuff I googled to be any use so far.