18 Nov
2008
18 Nov
'08
11:29 a.m.
Wouldn't it be more sensible if the voltage
selection circuit [were]
designed so that if a particular jumper [were] open it always gave a
lower output voltage tyhan if that jumper was closed (all other
jumpers being set the same). Then an open jumper would not fry
anything.
That's predicated on the assumption that undervoltage is safe. I'm not convinced this is true; it seems plausible, even
probable, to me that
undervoltage can lead to excessive current draw and such things as
logic not working right, producing "impossible" conditions like
multiple drivers squabbling over bus lines. (Consider what SMPSUs do
when fed undervoltage.)
Yes, but SMPSUs do approximate a constant power load, so they draw more
current as the input voltage drops, hence the damage on too low an input
voltage. I would be suprised if any CPU chip had that property.
But yes, too low a voltage could case things like internal contentions if
2 drivers were turned on at once. I don't know if this is likely (I
don;t have any modern CPUs...) I also don't know how quickly this would
cause damage (would you have time to notice the machine wasn't even
attempting the POST and then turn it off before the CPU was damaged)?
But then
it's my bitter experience that good design and PC hardware
do not go together...
Preach it, brother!