12 May
2006
12 May
'06
2:04 p.m.
On Fri, 12 May 2006, Roger Merchberger wrote:
I need some help from those who are a lot better than
I in hardware design...
certainly not me
The problem is I need to use a PC power supply
(AT-class with it's own
power switch) as a 12V power source, and the only one I have access to
needs a minimum load of 3Amp on the +5Volt line.
By my rough calculations and allowing for wiggle room, I'd need a 20-watt
power resistor of 1.5 ohms to keep the critter happy. "Bare minimum" is
15W, and I could squeak by with that if I wire the fan to the 5V line
instead of the 12V... but even when I'm expected to perform a "miracle" I
like to have a little wiggle-room. ;-)
Problems I have are: 1) I need this by Monday, and 2) I don't keep 20-watt
power resistors in my back pocket. Had I a week, I'd just order the right
tool for the job - I don't have that luxury. ;-)
For temporary loads to check power supplies, I use automobile headlights.
For a 5V load, I use a 6v headlight (usedta be common)
They provide enough load, and even light up the workspace.