Running Constantly?

paratwa said:
By saying "inrush of current" you are talking about heat. Since anything that resists the flow of current (resistors) will cause heat. The more current you use the more something will heat up. It's also why when you overclock your CPU with more voltage, it heats up more.
Click to expand...

No, I'm not talking about heat. I'm talking about the stress that electronic parts are subjected to when electrical energy surges into them from a previously unpowered state.

For instance. A light bulb filament blows when the lamp is first turned on. Why? The resistance of the filament is extremely low when it the filament is cold. Switching on the current puts a temporary blast of many amperes into the filament until it reaches its full temperature, where the current drops rapidly as its resistance rises to normal levels. Tungsten has extremely low resistance when it does not emit light. Light bulbs last a lot longer when they're left to burn constantly instead of switching them on and off all the time.

Here's a wikipedia article on inrush current for capacitors:
http://en.wikipedia.org/wiki/Pre-charge

Here's an article on Inrush Current Limiters:
http://www.ametherm.com/Inrush_Current/inrush_current_limiters_pcim.htm



Tom
 
OvenMaster said:
No, I'm not talking about heat. I'm talking about the stress that electronic parts are subjected to when electrical energy surges into them from a previously unpowered state.

For instance. A light bulb filament blows when the lamp is first turned on. Why? The resistance of the filament is extremely low when it the filament is cold. Switching on the current puts a temporary blast of many amperes into the filament until it reaches its full temperature, where the current drops rapidly as its resistance rises to normal levels. Tungsten has extremely low resistance when it does not emit light. Light bulbs last a lot longer when they're left to burn constantly instead of switching them on and off all the time.

Here's a wikipedia article on inrush current for capacitors:
http://en.wikipedia.org/wiki/Pre-charge

Here's an article on Inrush Current Limiters:
http://www.ametherm.com/Inrush_Current/inrush_current_limiters_pcim.htm



Tom
Click to expand...

I agree that inrush was a problem with computers years ago, but all new power supply's contain a device to control inrush, some call it soft switching. It ramps up the voltages so that it is not one big jolt to the system being powered.

Even in your modern stereos and t.v's they use the same device.

So the effect of inrush has been drastically reduced over the last few years in an average power supply.

Light bulbs on the other hand have no source of soft switching, it is either all on or all off. It is mostly the heat that is caused by the filament burning that reduces the life of the bulb. Constant heating and cooling weaken it so that eventually the inrush of current breaks it. That's why light bulbs very seldom just burn out while on. They get to the point where they are so weak from the heat cycle that they break when next turned on.


So in computers, the heat cycle causes the componet to weaken and the "inrush" shoves it over the edge.

http://invsee.asu.edu/nmodules/lightbulbmod/burnout.html


http://ask.yahoo.com/20041228.html
 
The hard drive will eventually wear out from having to start and stop, but that may be quite some time in the future ;)
 
Jet said:
The hard drive will eventually wear out from having to start and stop
Click to expand...

very true, i thinks its better leaving it on for extended periods than shutting it down all day.
I personally never shut my work PC down when i leave at 4, i leave it on the only day i shut down is friday, so it gets the weekends to rest.
As for my home PC i never shut it down, rarely,i use external fan to cool it, when the temps go high
 
It depends on how old the stuff is too. The closer the stuff is to end of life the less likely it is to come back on if you turn it off.

As long you aren't turning your PC on/off many times a day it will last more than long enough.
 
eh i turn mine off every night because of the lights..

Wait, i can turn off all my fans/lights with the switch's i put in :eek:
 
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