jeff@abnji.UUCP (jeff) (03/12/85)
[why do transformers hum? Because they don't know the words]
The March edition of Radio Electronics has an article describing
how to build your own UPS. It's a DC to AC converter (12VDC in,
120VAC out). They show the waveform, and it obviously is more of a
square wave than a sine wave. They did not reccommend it for use with
everything, and since computers were not explicitly mentioned I'd
say it is NOT suitable for use with micros.
Jameco's Winter Flyer is out and they have the following
from Data Shield
model AT800 800 watts of power & sine wave output $800
model AT500 500 watts of power for most multi-user PCs $700
model XT300 300 " " " $400
model PC200 200 " " " $300
also of possible interest
model S75 surge protector with a 200 joule rating $50
(most others I've seen are only 70 joules)
hope this is informative
Jeff Skot
{ ihnp4 | mcnc | cboscb} abnji ! jeffhenry@utzoo.UUCP (Henry Spencer) (03/13/85)
Some of the paranoia about feeding square-wave ersatz AC, from a UPS,
into a computer power supply may be overblown. Our electronics man
reports successful operation of quite a variety of devices, including
floppies, VTRs, monitors, etc. from a square-wave power source. He's
interested in knowing peoples' reasons for wariness about square-wave
AC; if you've got anything specific, mail him at the address below.
He knows *some* of the reasons, but wants to know if there are others.
Wern Thiel
U of Toronto Zoology Electronics
{allegra,ihnp4,linus,decvax}!utzoo!wern NOT just 'r', he's not me
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry