16 Nov
2004
16 Nov
'04
2:41 a.m.
At 11:15 AM 11/16/04 -0500, you wrote:
At 10:25 AM 11/16/2004, you wrote:
OK I just picked up some computers with 150 Amp 5 volt supplies. Now figure out the
necessary resistrance and wattage and go find me a resistor :-)
Joe
Ed> Old disk drives, if they'll at least
spin up, make good dummy
Ed> loads. The AC setting on a voltmeter will let you know if you
Ed> have too much ripple on a DC supply.
Depends on the voltmeter...
Actually, a resistor is a classic dummy load. They have the advantage
of being dirt cheap, and readily available in thousands of
variations. If Radio Shack doesn't hack it, Digikey certainly will.
Yup!
Well, for +12 and +5 you'll need two resistors though.
Power rating? [time spent pondering] 12v 1A = 12w, 5v 1A = 5w should do it. Ooops, no 12 ohm or 5 ohm power resistors, got a bunch
of 1 ohm ones,
so I can series/parallel a bunch of them ....
Screw it, they're not that much, maybe a couple of buck each.
Then connectors (what's the Molex part number?), and wires and heat shrink
and solder,
maybe a perf board to hold them, or a minibox
[project creep occurs, more features, more time, more money, CCTALK piles up]
then shipping expense (and time) from Digikey, or gas and AGGREVATION going
to RadioShack
["No, I already have a cell phone and Internet thanks, where are the
components, way in the back?"
then a wait at checkout as Granny gets a new hearing aid battery]
Maybe $10-$20 bucks,
Ooops, got to go back for the terminal lugs I forgot, or DigiKey was out of
stock on.
Vs.
Pull old XT2190 or ST251 from junk box,
plug in power supply lead, done.
Cost = 0, time = 1 minute, satisfaction at not having to go through above
nonsense = priceless!
(plus giving more time to keep up with CCTALK email and for composing
thoughtful email responses like this one! <g>).
:-)
I got an ATX power supply tester a few months back after a rash of bad ATX
power supplies.
Very handy.
Thought one for AT type power supplies would be good too.
Hey, just a few resistors for +12, +5 and some LEDS's, no sweat.
STILL working on it, or rather it's still not been done.
Got a box full of junk MFM drives, they work fine for this.
PLUS! the inductive loads and relay kicks from old drives might be better
than resistors anyway [thereby breathing more life into this thread].
Ed K.