Circa Sat, 19 May 2007 00:57:01 GMT recorded as
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[email protected]> looks like "Andy C"
yes, that is exactly what i had planned - we have a dedicated PC to run the
software for the CCTV cameras and i was hoping to run the cameras from one
of the 12v supplies from this functioning pc...
how so ? the computer PSU boasts 500watts - wouldn't 4amps @ 12volts be a
puny external load ?
That rating is for the entire supply. Most of that rating will be for the
5V and 3.3V rails. You have to look at the specs for the individual
outputs. Suppose the 12V output is rated at 15A. That seems like plenty,
but have you spec'd and measured what the MB and peripherals are drawing?
Suppose that total is typically 10A. Now you risk topping out the PS, and
causing a voltage droop under full load.
Furthermore, you will have no isolation on the 12V rail between the
computer peripherals and the cameras you want to use. Noise and
instability from any one device will affect all other devices on the rail.
So you are faced with doing a complete load analysis on the computer and
the cameras in order to find out whether or not this idea is feasible.
All that instead of spending $25 on a 12V 5A dedicated switching supply.
It just doesn't make sense, unless you are more interested in experimental
engineering than creating a workable, stable system. What if something
unpredictable happens with the bus you have routed external to the
computer, and you wipe out your hard drive? To me, the cost-risk-benefit
analysis is weighted very much in opposition to the shared bus idea.
and you are not using these and there is 50W of 12V
