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Causes of the CPU's warm-up.

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l_r_c_t   10-21-2009 at 02:02:50 PM

Hello Everybody:

I recently heard from my Electronics teacher the cause of the CPU warm-up.

The computer works in a binary system and the difference between "1" and "0" is the difference between the voltages supplied to the CPU. When a certain voltage level is translated to "1" and another voltage level is translated to "0".
The warm-up is caused by the voltages in the middle, which the CPU can't handle and decide if they are "1" or "0".

(The whole explanation was given, like if the CPU and the voltages were personalities, but of course it was a way of expressing.)

The whole explanation was given by my Electronics teacher, so it should be right, but can someone write a deeper explanation?

Is the reason written above is the only reason why the CPU warms up? I think that there is a direct relation between the load given to the CPU and his temperature increasement.

Thank you.

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CompuTronix   10-21-2009 at 11:45:42 PM
- 1 +

l_r_c_t,

CPU's dissipate a specific amount of power (W) at idle, simply because voltage (E) is constantly applied to millions of nano transistors which have resistance (R), and consume current (I).

DC Ohms Law: E = I x R
DC Watts Law: W = I x E

When any transistor changes logic states from "0" to "1" or "switches" from "off" to "on", voltage (E) is applied to the Base or Gate of the NPN or PNP junction, which has resistive (R) properties, so it consumes more current (I), which dissipates more power (W), which is converted into heat.

Clear enough?

If you'd like to learn more about processor temperatures, then perhaps you might like to read my Temperature Guide. Just click on the link in my signature.

Comp :sol:


Message edited by CompuTronix on 10-21-2009 at 11:49:36 PM
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sminlal   10-22-2009 at 12:25:08 AM
- 0 +

l_r_c_t wrote :

The warm-up is caused by the voltages in the middle, which the CPU can't handle and decide if they are "1" or "0".

That's a bit of an oversimplification. Transistors "leak" tiny amounts of current, and when you multiply that by almost a billion transistors it becomes significant.

Not only that, but the CPU clock switching billions of times a second means that an awful lot of those transistors are usually switching state, and with every state switch they go through that "middle" zone. This is why many modern CPUs ramp the clock speed down or disable entire blocks of circuitry (such as the floating point unit or an entire core) when those units aren't in use.

Reply to sminlal
4745454b   10-22-2009 at 05:50:34 AM
- 0 +

A transitor with a voltage applied to it (1) will raditate heat as well would it not? Thats when "leakage" happens, not in the between state. A transistor with no voltage (0) would emit no heat. A transistor at 1 will emit the most. I would say either your teacher got it wrong, or you misunderstood.

------------------------------ The voice of REASON
Do NOT feed the TROLLS!
Always a DEMON!
 Reply to 4745454b
l_r_c_t   10-25-2009 at 11:18:18 PM
- 0 +

Hello again:

 

Today I went again to my electronics teacher and told him about the reasons that you all mentioned, and also about my idea of what is the reason (load of the CPU), and he told me that both of them are right in a certain way; at the moment the user loads the CPU with tasks, the CPU's transistors has to switch more times between "1" and "0", what makes them spend more time in the "dead zone" (not "1"/"0" ).

 

So apparently, at the first time, I understood my teacher, but not completely. But now, after your and my teacher's explanations I fully understand it.

 

Thank you all!


Message edited by l_r_c_t on 10-25-2009 at 11:20:44 PM
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4745454b   10-26-2009 at 07:45:36 PM
- 0 +

I still disagree with the teacher. Heat happens when you have a voltage applied to a transistor. Your making it sound like he says heat happens at the "dead zone", and not when its at 1. Voltage = heat, and voltage = 1, so heat = 1. Unless you guys are discussing something else, or I've missed something horribly.

------------------------------ The voice of REASON
Do NOT feed the TROLLS!
Always a DEMON!
 Reply to 4745454b
CompuTronix   10-26-2009 at 07:54:57 PM
- 0 +

Didn't Verizon do several "Dead Zone" commercials? :lol: I think the teacher is in the "Twightlight Zone"! :kaola:

Reply to CompuTronix
4745454b   10-26-2009 at 07:59:02 PM
- 0 +

LOL, possibly. That or the teacher doesn't understand what he's talking about. Looking back to my college days, that could be whats going on as well.

------------------------------ The voice of REASON
Do NOT feed the TROLLS!
Always a DEMON!
 Reply to 4745454b
CompuTronix   10-26-2009 at 08:05:04 PM
- 0 +

I agree. Someone is confused, or is being confused by someone, or both! :pt1cable:

Reply to CompuTronix
l_r_c_t   10-27-2009 at 02:40:10 PM
- 0 +

Alright for all of the "funny" guys; When I wrote "Dead zone" I meant to the situation where the CPU is at, when the transistor switches from "1" to "0".

And as for "4745454b", your point sounds right, but still this is what my teacher said, which also sounds right.

So again I got back to the same situation, after I thought I had it.

I will ask my teacher again which by the way has an academic degree (Electronics), to all of those who underestimated him, and see if I can get deeper in this issue.

Thanks for now.

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CompuTronix   10-29-2009 at 09:06:52 AM
- 0 +

l_r_c_t wrote :

I will ask my teacher again which by the way has an academic degree (Electronics)

Some of us here also have bachelor's degrees in electronics, and have also been instructors. I once had an instructor who, although he understood the material, his delivery was so lame compared to other instructors, that most in our class agreed he was making the material confusing, and more difficult to clearly understand.

Does this perhaps sound familiar?


Message edited by CompuTronix on 10-29-2009 at 09:07:36 AM
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l_r_c_t   10-29-2009 at 05:59:03 PM
- 0 +

First, I didn't and don't intend to underestimate anyone.

I am not sure about my teacher's explaining abilities (he is my instructor for barely 2 months).

I learn electronics for already three years (this year being the fourth), and I never had a teacher who really knew the subject as deeply as he knows it. There is a chance that his delivery is not as good as some other teacher's, and when thinking about it, his explanation wasn't while sitting, and talking about it, it was in the middle of the hallway, standing and while he was in a rush.

I will ask him again on Sunday, and this time, I'll ask him for a more detailed explanation, and I will write it down.

I hope to get back with answers on Sunday, and until than thank you for your attention.

Reply to l_r_c_t
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