Strange effect of my laptop

[Irakli]

Hi All,

Here is my question and please do not laugh, it is the serious post.

When I put my laptop on my lap (actually little bit higher, you know what I mean), I always have a burning sensation in that area of the body. The effect is not marginal, actually it is quite real up to the point of mild pain.

I was wondering if anybody else had similar experience and what might be a cause.

I have a trifield meter (model 100XE) and it does not register any radio/microwave and Electric fields close to the laptop edge. However, it registers around 50milligauss of magnetic field. Any ideas?

 

[JMFahey]

It´s real and no mystery.
The laptop includes a switching power supply to get different voltages needed, there actually is a "hot spot" on the underside.

 

[gpapag]

It’s real.
Thermal issue.
Take measures against it

Burn Injury Caused by Laptop Computers

Erythema ab igne - Wikipedia, the free encyclopedia

George

 

[chris661]

I have a piece of MDF, 10" x 18" that I put my laptop on when using it on my lap. I gives me space for my mouse, and ensures any connectors I plug in (headphones etc) don't get bashed from the side.

Chris

 

[Irakli]

so, if it is purely thermal, any black object with the same temperature should give the same effect. I do not think this is a case. I guess I need to do an experiment.

 

[kevinkr]

All of my older laptops did this, my latest, a now 3yr old Dell does not. The temperature across the bottom of those laptops rose to something like 120 degrees F when I had them sitting on my lap. Sitting on a table the bottom of the one I checked ran about 10 - 15 degrees cooler. The new one barely warms up at all.

 

[DF96]

so, if it is purely thermal, any black object with the same temperature should give the same effect.

Which black object at which temperature? The issue is not case temperature in free air, but case temperature when fed from a higher temperature heat source inside and with heat flow blocked by a good heat insulator (your lap) with its own heat source too (your metabolism).

One way to reduce laptop heat is to get rid of as many background tasks as possible. This will also lengthen battery life. The idea is that when the CPU has nothing to do it will go to sleep for a brief while and so consume less current. Cycling around checking for things to do consumes power. Although NT (the underlying operating system) has a proper pre-emptive scheduler I suspect that this feature is not always properly exploited by software so there may be vestiges of cooperative scheduling still going on.

 

[mcandmar]

Most likely your covering up the vent holes impeding ventilation = hotter running cpu and internals.

 

[kevinkr]

+1

 

[Mooly]

Its worth checking you are not running lots of background processes. The more that run, the more the CPU has to work overtime to service those processes. Result. Heat ! and lots of it.