-=PCTechTalk=- Re: My LCD produces too much heat?

Rudy,
    No part of my description here takes into account devices that are 
actually designed to produce heat as their basic function such as electric 
clothes dryers, electric space heaters, electric water heaters, etc..  Those 
intentionally convert electricity into heat.  I will only be discussing 
unintentional heat generation here.

    At its simplest form (and within the context of electronics and the 
components it brings to life), operational heat is generated as a result of 
friction at the molecular level.  As current travels through a wire, there 
is a certain amount of resistance as electrons jump from one atom to the 
next on their way to the other end of the line.  While most of the 
electricity will reach its intended target (the appliance at the end of the 
line) and be converted into other types of energy (it'll make a blender spin 
or a washing machine pump water), this resistance results in a little bit of 
heat (and a subsequent loss of a small amount of that initial electrical 
potential) that actually warms up the wire.  Attach too many appliances to 
the same extension cord and it'll REALLY heat up, so much that it becomes a 
fire hazard since the heat generated can eventually melt the protective 
insulator and cause a short circuit or worse.

    With electronic components such as a CPU, they are made up primarily of 
microscopic transistors that are constantly turning on and off to direct 
data through itself.  The switching is accomplished by applying a voltage to 
what is called a gate.  Depending on the type of transistors employed, the 
presence of voltage at the gate allows current to pass from one side of the 
transistor to the other.  The absence of voltage will instead turn the 
transistor off.  Since there are hundreds of millions of transistors in a 
modern CPU and those switches operate at astronomical speeds (measured in 
Ghz.), a LOT of heat is produced by all of the miniscule resistances present 
throughout the processor.  As more transistors are added to CPU designs and 
the faster they make the chip, the more heat it will produce simply because 
there will be more places for resistance to fight against the flow of 
electricity.  Fortunately, they have been working towards reducing the size 
of the transistors used in these beasts.  Each reduction in transistor size 
allows them to operate using less electricity and that means less electrical 
resistance and therefore less heat.

    I could go into a lot of additional examples, but I think those two 
should help explain that the heat originally produced is a product of the 
electricity that never gets to be used for whatever the component is 
supposed to do.  Operational heat results in the loss of a tiny percentage 
of the actual electricity used by the component or system, even if the heat 
produced is almost unbearable.

    As far as your LCD goes, there are fluorescent lamps behind the window 
you stare at all day.  They operate by exciting the electrons within a gas 
inside a vacuum sealed tube when voltage is applied to them.  This gas has a 
much smaller resistance than the filament found in incandescent bulbs (the 
screw in type found in many table lamps), so they don't natively produce 
anywhere near as much heat as incandescent lamps.  They also cannot produce 
anywhere near as much heat as your tower.  Just consider the fact that your 
Hanns only uses 49 watts Max of electricity (watts = voltage X amperes) 
compared to hundreds of watts being used by the tower.  Of course, this 
doesn't mean fluorescent lamps don't get warm over time, just not to the 
degree you are questioning here.  LCD monitors and TVs should all have vents 
to allow heat to escape rather than build up within the confines of the 
casing.  If these vents are covered, clogged, etc., I could see this problem 
developing after a while of continuous monitor use.  If the vents are 
unobstructed, consider the placement of your tower.  Is it possible that the 
heat is actually rising up from the back of the tower and making it seem 
like it's coming from the monitor?  In our computer room, the two nearly 
constant running towers certainly do act as room warmers as you described, 
but the two LCD monitors add very little to that equation.

Peace,
G

"The only dumb questions are the ones that are never asked"

----- Original Message ----- 
From: "rudy" <rudylopeznc@xxxxxxxxx>
To: <pctechtalk@xxxxxxxxxxxxx>
Sent: Saturday, June 28, 2008 3:39 PM
Subject: -=PCTechTalk=- My LCD produces too much heat?


> If I am correct, all power used by a computer ultimately turns into heat,
> correct? LCD uses much less watts than a CRT but why does heat seem to 
> pour
> out of the front of my Hanns-g 22" LCD after long useage? Uses 49 watt Max
> http://www.newegg.com/Product/Product.aspx?Item=N82E16824254020#spec
>
> The heat given off by a computer depends on several things. Type and speed
> of the CPU.
> Type, size, and efficiency of the CPU cooler. Cleanliness of the CPU 
> cooler.
> How many and what type of PCI cards you have installed. Case design and
> number/type of case fans are fitted
> Ambient air temperature in the room. How hard the CPU is working (i.e. 
> what
> process it is running) Type of graphics cardMake and design of the
> motherboard. ( I haven't gone Gman techie here, just relaying what I have
> read )
> http://club.cdfreaks.com/f7/how-much-heat-does-computer-give-off-187993/
>
> The heat doesn't seem to generate from the desktop up to the LCD and 
> through
> it, maybe this is possible? It sure warms the room up, great in the Winter
> but not so in the Summer. Any other LCD users feel the heat from the front
> panel of your LCD? Thanks and a happy weekend to all.
> Rudy
>
>
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