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temperature limits

June 29, 2005 at 15:25:03
Specs: Windows XP Professional, Athlon XP 1700+ / 640mb S

hi, im just wondering, what are the upper and lower limits to pentium 2 processors. not just the cpu itself, but with a heatsink and fan, and running

ie, if the computer was in an environment where the temperature was 0 celcius, would it work? how about one at 30 celcius. would the computer run ok? or would it have difficulties (this is under the assumption that there are no other problems like moisture or whatnot)

Dave


Dave


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#1
June 29, 2005 at 15:41:41

Disregarding moisture and condensation there is no lower limit that a CPU will run at.

All electrical components work more efficiently at lower temperature, the lower the better. It reduces the resistance within the circuit, therefore current consumption and consequently heat until you get down to absolute zero (-459F) when the resistance in an electrical circuit is zero.

Conversely, higher ambient temperatures increase the resistance, thus increasing the current flow and generating more heat. When this happens you can get into a situation called thermal runaway but power supplies have circuits to prevent this from happening.

Stuart


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#2
June 29, 2005 at 15:45:45

Having thought about it, there has to be a lower limit before you get to absolute zero because at absolute zero everything conducts electricity and therefore you would have no semi-conductors.

However, I think that temperature is going to be pretty low, lower than you would meet in any normal circumstances.

Stuart


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#3
June 29, 2005 at 16:24:00

ok thanks. so if thats the case, heres something more specific. the computer will be subject to outdoor temperatures (-15 to +40 at the greatest, more like -10 to +30), but in an enclosed space, where it will not experience the weather, just the temperature

any possibility of failure, again, not including moisture?


Dave


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Related Solutions

#4
June 29, 2005 at 17:23:31

Excellent post by Stuart.
When you have wide temperature variations you are exposing the PC to two conditions that can eventually cause problems. One is moisture condensation and the other is expansion and contraction, which can cause fragile connections to break.



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#5
June 29, 2005 at 18:58:45

A lot depends on how much the temperature varies. With a temperature between -10 and +30 C you will get condensation - there is no avoiding it unless you have some pretty good air conditioning units that will take all the moisture out of the air.

As air heats up it absorbs moister and as it cools the moisture precipitates. Thats how we get rain and snow.

Being in an enclosed space will not help much unless it is airtight. As soon as you open the door on a warm day, the warm moist air enters. As it cools to -10 you will see just how much moisture air can hold. The only places you will get temperatures of 30-40C and dry air is in the desert.

Stuart


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#6
June 30, 2005 at 02:24:36

From my Dell Dimension 8400 manual:
Quote
Environmental

Temperature:
Operating 10° to 35°C (50° to 95°F)
NOTE: At 35°C (95°F), the maximum operating altitude is 914 m
(3000 ft).

Storage –40° to 65°C (–40° to 149°F)

Relative humidity 20% to 80% (noncondensing)

Maximum vibration:
Operating 0.25 G at 3 to 200 Hz at 0.5 octave/min
Storage 0.5 G at 3 to 200 Hz at 1 octave/min

Maximum shock:
Operating bottom half-sine pulse with a change in velocity of 20 inches/sec
(50.8 cm/sec)

Storage 27-G faired square wave with a velocity change of 200 inches/sec
(508 cm/sec)

Altitude:
Operating –15.2 to 3048 m (–50 to 10,000 ft)
Storage –15.2 to 10,668 m (–50 to 35,000 ft)
End of quote

Bryan


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#7
June 30, 2005 at 05:36:41

I suspect the reason for such a high low temperature of 10C in this case is the hard disk.

Hard disks are particularly sensitive to temperature variations so much so that they have mechanisms to re-align the heads automatically to account for expansion caused by heat generated in use. There is obviously a limit to the amount of correction that can be made.

An excessively low temperature could cause the heads to get way-out of alignment not to mention that at -40C metal, especially aluminium, can get quite brittle.

Stuart


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