Why does electrical equipment get hot?
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In my PC I have one whopper of a CPU heat sink and more fans than you can shake a stick at, this is because I know these components get hot. But what causes this heat? Is it some type of friction down on the atomic layer, or what?
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
Desn't it relate to the fact that transistors MOS in circuits clash for a small amount of time causing heat ? (I may be wrong on that one my electronics courses are a long way back)
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It gets hot for the same reason an electric space heater gets hot. Electrical voltage applied across a resistance creates heat energy. Conservation of energy and matter stuff. A processor is a huge collection of very tiny resistors. If you have a 1000 ohm heating element (aka resistor), and you apply 110 VDC (keeping it simple with DC instead of AC, leaving power factors and inductive resistance for another day), you can figure out how much power is used. Voltage = E Current = I Resistance = R Power = P P = I*E E = I*R thus I = E/R (see [^]) so, P = E*E/R = 110*110/1000 = 12.1 Volt-amps or in common terms, 12.1 watts Now, lets assume there are 800 million transistors (which are also considered resistors) in a given processor. From what I've read, typical desktop processors generate 80-100 watts, and laptop processors typically 30-40 watts. It's just simple laws of electricity, nothing magical.
MSBassSinger wrote:
From what I've read, typical desktop processors generate 80-100 watts, and laptop processors typically 30-40 watts.
At least for desktops your numbers are a bit high. Except on the very high end the norm now is ~60W. Very high end chips are different since the OEM itself does the same bigger heatsink and higher voltage stuff that is done by overclockers in the factory. Also those numbers are at max load, in normal circumstances they draw less, especially in the laptop end.
-- If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.
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the power supply, through the use of a catalyst, turns atmoshperic CO2 and water vapor into methane and ozone (that's what the fan is for). the ozone is passed over an enzyme, which converts it to oxygen, which is released (through the fan). the methane molecules are chained together forming kerosene through non-aqueous osmosis. the kerosene is then burned to power your computer, and that's where the heat comes from.
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In my PC I have one whopper of a CPU heat sink and more fans than you can shake a stick at, this is because I know these components get hot. But what causes this heat? Is it some type of friction down on the atomic layer, or what?
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
Every time the computer converts a one to a zero, a little man in a logic chip has to erase the one and draw a zero. Likewise for converting a zero to a one, erase the zero and draw the one. In the early days, logic was maintained on a bunch of little magnets organized into a "core". In these magnetic core memories where you could see the little magnets, the orientation of the magnetic lines was used to represent a one and a zero, instead of actually writing the one or zero. These tended to heat up less, because the virtualization of the one or zero was based on the direction the little man was last running on the magnet. Little work was involved (other than running from magnet to magnet, which was shortcut by adding additional running track wires between magnets) and there was more air space inside the core than today. What is unique is that you can actually watch the little man reversing direction on the magnet. Today, the memories are much smaller (as is the little man), so there are much more ones and zeros to change. The little man has to run around a lot more, so they added more little men on the chip. But they are being asked to do this ever more quickly, so they still must run faster. The pathways are ever smaller and the penalty for crossing over the pathway out-of-bounds is exacerbated, adding a certain level of stress. All of this running around, being stressed out creates the heat. :mad: Computers have power supplies which change the dangerous input voltage to tiny little volts. These little volts are used as Electrical little-Man Prods [or simply EMP ] - similar to cattle prods - to keep the little men working smoothly under threat of what's to come. More little men, more power is needed, but there is no direct correlation between the power requirements and the heat - it is an indirect association at best. However, the power supply also creates a standing static charge. This attracts the bits of used eraser out of the chip. Originally, a single fan in the power supply fan was sufficient to clear these eraser bits away from the chips. PC designers added more fans as a gesture of kindness. It keeps the little men happy. Not only does it remove the little eraser bits more efficiently, but it cools down the little men. The happier they are, the faster they'll work (opposite of Labor Unions). More
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MSBassSinger wrote:
From what I've read, typical desktop processors generate 80-100 watts, and laptop processors typically 30-40 watts.
At least for desktops your numbers are a bit high. Except on the very high end the norm now is ~60W. Very high end chips are different since the OEM itself does the same bigger heatsink and higher voltage stuff that is done by overclockers in the factory. Also those numbers are at max load, in normal circumstances they draw less, especially in the laptop end.
-- If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.
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dan neely wrote:
At least for desktops your numbers are a bit high.
Hmm, then why did I have to replace my 350 Watt PS with a 450 Watt? I have 9 fans pumping out the heat - but only when I'm typing.... :)
Gary
What did you upgrade from? What else did you change at the same time as your CPU? Even though CPU power consumption has apparently peaked and turned downward a bit on the low-midrange end, graphics hardware in particular is consuming ever more power. Top end nVidia cards are drawing almost 200W, ATIs topend card is at 225W. Consumer level cards haven't grown nearly that fast but there's some growth there as well. Unless you have major airflow problems with an apparently low to mid range system 9 exhaust fans is major overkill.
-- If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.
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What did you upgrade from? What else did you change at the same time as your CPU? Even though CPU power consumption has apparently peaked and turned downward a bit on the low-midrange end, graphics hardware in particular is consuming ever more power. Top end nVidia cards are drawing almost 200W, ATIs topend card is at 225W. Consumer level cards haven't grown nearly that fast but there's some growth there as well. Unless you have major airflow problems with an apparently low to mid range system 9 exhaust fans is major overkill.
-- If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.
dan neely wrote:
What did you upgrade from?
Two hard drives and RAM seemed to have tipped the scale. On warm days, the system would shut down at inopportune moments. So, replaced everything with new CPU, GPU, 2 more HD, another DVD, pretty lights. Big tower - lot's of space. Eliminated ribbon cables. No airflow problems now. PS fan, CPU fan, Graphics fan, 4 LED output fans, 2 input fans. Hums right along. Know what I mean?
Gary
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It's because of all the smoke moving around inside the cpu getting the work done. It's a little-known fact that all electronic equipment works using smoke. It is for this reason that when you let the smoke out, it stops working. ;)
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If it didn't need power you wouldn't have to plug it in. Most of the power is turned into heat, a bit into other radiation - light, radio, x-rays if a CRT, and some sound. A tiny tiny little bit of energy might be stored in a flash memory device. I'm not sure if anyone knows the limits of how much energy is actually needed to process / store information (interesting philosophical question - it is Sunday), but I suspect that it is many orders of magnitude less than we use.
Peter "Until the invention of the computer, the machine gun was the device that enabled humans to make the most mistakes in the smallest amount of time."
In principle, a computational device does not need to create any heat if no information is lost in the computation. This usually means returning the question along with the answer at the end of a computation. So now we have the design, we just need those engineer types to work out the details.
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dan neely wrote:
What did you upgrade from?
Two hard drives and RAM seemed to have tipped the scale. On warm days, the system would shut down at inopportune moments. So, replaced everything with new CPU, GPU, 2 more HD, another DVD, pretty lights. Big tower - lot's of space. Eliminated ribbon cables. No airflow problems now. PS fan, CPU fan, Graphics fan, 4 LED output fans, 2 input fans. Hums right along. Know what I mean?
Gary
ghle wrote:
Hums right along. Know what I mean?
yeah, I've largely moved my cooling over to 120mm low speed fans instead of faster 80mm ones. Not silent, but much quieter.
-- If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.
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ghle wrote:
Hums right along. Know what I mean?
yeah, I've largely moved my cooling over to 120mm low speed fans instead of faster 80mm ones. Not silent, but much quieter.
-- If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.
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In my PC I have one whopper of a CPU heat sink and more fans than you can shake a stick at, this is because I know these components get hot. But what causes this heat? Is it some type of friction down on the atomic layer, or what?
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
What is heat? Vibrational energy (and in gases, translational and rotational, as well). Do not confuse this with the 'warmth' coming off of your system, which is energy in the form of radiation (to keep it simple, we'll say it's infrared). The IR radiation is one of (beloved) entropies methods of dispersing concentrations of energy - it's way of transferring it through a vacuum. (Yes, we've convection, as well, for those fans to assist). First of all, whilst electricity moves through your equipment (and everything else) at the speed of light, ELECTRONS DO NOT! They actually move relatively slowly. In order to travel through a medium, they must overcome resistance. This has quite a few sources: A lot of it is electromagnetic in nature, wherein the induced fields ultimately are inopposition to the fields that induced them. This is working on the wave-nature of the electricity (i.e., an alternating current of rather high frequency these days). One way you can help yourself get a feel for one of these is that the structure (of a conductor) at the atomic level is trying to reorient itself with the field. There is always some degree of lag; the two fields are thus in some degree of oppostion. Back to those moving electrons: as they seep through your system, they are not moving smoothly, but rather from one region of lower potential energy to another. This structure is due to the atomic structure of the conductive medium. The regions are damn small. However, to move up the hill (so to speak) from one region to the next, requires energy (i.e. a push we call voltage). This extra push we may call a work function (certain license taken with the term). When it goes back down to the lower energy state, the energy is released - well MOST OF IT. That bit left over, which was part of the electron/atom system was distributed about the entire system to some extent. That bit left over is dispersed into atomic (better said, Molecular) motion. Your getting hotter. This disperses from electronic through vibrational, &etc. modes (degrees of freedom) - another pleasure from our friend entropy perefers this. You always 'lose' a bit, even though you're going up & down the same hills of energy. No free-wheeling coasting. It has to do with the irreverability of real systems. Basically a universal tax on everything. This should be enough (for now).
"The difference between genius and stupidity is that genius has its limits." - Albert Einstein
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In about 100 years, physicists will discover that there's something smaller than quarks even. Hamsters spinning in little cages. So, give those hamsters a rest and turn your computer off. :) Marc
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In my PC I have one whopper of a CPU heat sink and more fans than you can shake a stick at, this is because I know these components get hot. But what causes this heat? Is it some type of friction down on the atomic layer, or what?
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
What generates the heat is the power dissapated by the component. Energy is used and must be converted to some other form of energy, in this case heat. My understanding is that as you increase the clock frequency of a transistor, you get more leakage current, and in line with Power = Voltage x Current, you have power that needs to be dissapated, hence the heat.
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In my PC I have one whopper of a CPU heat sink and more fans than you can shake a stick at, this is because I know these components get hot. But what causes this heat? Is it some type of friction down on the atomic layer, or what?
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
Thanks to all who took the time to reply - even those with comedy answers (hint: don't give up the day job guys :) ) - I find the whole subject absolutely fascinating, and am even now inspired to do an evening course in electronics! I got frustrated with CP not letting me vote y'all a 5 at the same time, so even if you didn't get one consider yourself on my Christmas card list!
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
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dan neely wrote:
faster 80mm ones. Not silent, but much quieter.
Sorry, can't hear you... :((
Gary
If you want a decent quiet case, I can thoroughly recommend the following: Antec Solo Case 2 x 92mm Nexus Real Silent fans in the front 1 x 120mm Nexus Real Silent fan in the Rear 1 x Noctua CPU heat sink and fan This thing is very, very quiet and cool, which is no bad job given I have: Q6600 8GB Corsair "go faster" stuff 2 x 8800GTS's 2 x 150GB Raptors 2 x 500GB Samsung Spinpoints :)
Me: Can you see the "up" arrow? User:Errr...ummm....no. Me: Can you see an arrow that points upwards? User: Oh yes, I see it now! -Excerpt from a support call taken by me, 08/31/2007
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If it didn't need power you wouldn't have to plug it in. Most of the power is turned into heat, a bit into other radiation - light, radio, x-rays if a CRT, and some sound. A tiny tiny little bit of energy might be stored in a flash memory device. I'm not sure if anyone knows the limits of how much energy is actually needed to process / store information (interesting philosophical question - it is Sunday), but I suspect that it is many orders of magnitude less than we use.
Peter "Until the invention of the computer, the machine gun was the device that enabled humans to make the most mistakes in the smallest amount of time."
Actually not that philosophical. There is a discrete amount of energy that electronic engineers and solid state physicists have agreed upon as the minimum amount to accurately represent digital quantities. We are a few orders of magnitude from this number still but the gap is closing fast. Additionally, when designing a power supply circuit, to deliver optimal energy from your voltage source, you have to dissipate(emit as heat) as many watts of power in the supply as you do in the target circuit. And why do computers use energy in the first place? Computers used to use a lot more energy before they started using CMOS (complimentary metal oxide silicon) technology. Thanks to CMOS technology energy is technically only dissipated when a logic gate switches state from 1 to 0, CMOS is larger, more difficult to fabricate, and slower than other logic technologies but overcomes the heat and energy barriers and therefore in practical applications can be fabricated to be smaller and faster.