Antistatic Question

[matrix2]

Hey Guys i came across a Antistatic chair mat. I want to know if you touch a working pc case while statically charge if you can damage it ? This is the ad below with a link.

ANTI-STATIC CHAIRMATS


Trans-Stat® mats dissipate electricity without ground cords.
Ultra-clear vinyl.
Beveled edge (up to 46 × 60) for safety and easy rolling on and off the chairmat
Hundreds of Anchorpoints® to secure mat to carpet.
Trans-Stat® meets government standards for electrostatic properties of materials in accordance with Federal Test Method Standard 101B, Method 4046.


Antistatic mat

 

[jagec]

it's VERY unlikely that touching a PC case would damage anything...VERY. I can think of a few possibilities, but they involve very thin cases and very poor grounding.

 

[dkozloski]

Here in Alaska , the winter time humidity levels approach zero and the static electricity becomes ferocious. The only effect I have notice in years of this environment is that if you don't discharge the static on your body by touching the case first, it can lock up your mouse and you have to reboot everything to get going again. In nearly 50 years of experience with military and industrial electronics I have never seen an installed electronic device permanently damaged by a static discharge, only during installation.

 

[silverpig]

It'd have to be a damn big shock.

 

[Geniere]

Guys i came across a Antistatic chair mat. I want to know if you touch a working pc case while statically charge if you can damage it ? This is the ad below with a link.

Touching only the pc case is unlikely to ever cause a problem. Touching the keyboard or mouse increases the odds for a damaging discharge but usually not a cause for concern. Touching an unshielded cable is more troublesome. Touching circuitry within the pc case is the highest cause for concern, the point where I start taking precautions.

Its VERY unlikely that touching a PC case would damage anything...VERY. I can think of a few possibilities, but they involve very thin cases and very poor grounding.

I'm thinking the grounding conductor is not vital for static protection as far as touching only the case is concerned, as the neutral, ground, and hot are probably capacitively coupled to each other in the psu. At least if I designed the psu, they would be. I would assume the psu would also have some series inductance in the hot and neutral lines also. The neutral would suffice to dissipate a static charge to ground. Of course the grounding conductor is desirable for other reasons.

I have never seen an installed electronic device permanently damaged by a static discharge, only during installation.

Few of us have as many solid state components may only have their life shortened and their failure cause is never known.

 

[aplefka]

I'm not quite sure what this would do for the case. Nor do I understand how it really works. Does it just emit charges or what? Looks like a pretty stupid product to me.

 

[ggjb]

The anti-static feature seems to be more of a gimmick than anything. Don't worry about static unless you have a lot charged up. And grounding yourself on the case is always a good practice when installing hardware.

 

[navyjay]

By design, the case is your system's ground. As stated above, it's highly unlikely that static charge will cause any damage to your system if applied here.

On a similar note, I was shocked (pun intended) when my electrically naive mother decided it was a good idea to vacuum over the video input cord of my monitor. The quick static buildup went up to the monitor while it was on and blew it out. I'm sure it was just a fuse or something that went, but it wasn't worth the $100+ to fix it when I could buy a newer and larger monitor for not much more.

Most integrated circuits have antistatic protection (essentially integrated pn junction diodes to vdd and gnd) built into the input pins. It's a necessity today to make packages idiot proof by allowing reverse voltages without blowing up a transistor junction.

 

[Tiamat]

Not sure if this is related, but what does this situation mean:

I touched my roommates computer case while it was on, shocked it, and it restarted. His case is all aluminum.
Nothing seems to be damaged, but I am uncertain as to why shocking the exterior of the case would restart the machine.

 

[Geniere]

Originally posted by: Tiamat
Not sure if this is related, but what does this situation mean:

I touched my roommates computer case while it was on, shocked it, and it restarted. His case is all aluminum.
Nothing seems to be damaged, but I am uncertain as to why shocking the exterior of the case would restart the machine.

Probably the current in the case created a magnetic field that in turn induced a current flow in one of the internal flexible ribbon cables. One of many possibilities.

 

[DrPizza]

Originally posted by: Geniere

Originally posted by: Tiamat
Not sure if this is related, but what does this situation mean:

I touched my roommates computer case while it was on, shocked it, and it restarted. His case is all aluminum.
Nothing seems to be damaged, but I am uncertain as to why shocking the exterior of the case would restart the machine.

Probably the current in the case created a magnetic field that in turn induced a current flow in one of the internal flexible ribbon cables. One of many possibilities.

I was going to comment that the static charge stays on the outside of the case, much the way the charge on a van de graff is on the outside of the sphere, rather than the inside; or the way a car protects you from a lightning strike (it's not the tires!)

I didn't think of induced currents.

 

[MetalStorm]

Originally posted by: Geniere

Originally posted by: Tiamat
Not sure if this is related, but what does this situation mean:

I touched my roommates computer case while it was on, shocked it, and it restarted. His case is all aluminum.
Nothing seems to be damaged, but I am uncertain as to why shocking the exterior of the case would restart the machine.

Probably the current in the case created a magnetic field that in turn induced a current flow in one of the internal flexible ribbon cables. One of many possibilities.

What I think is a more likely explanation is that by shocking the case, the charge would obviously be grounded through the PSU, this spike in the PSU's ground wire would probably have triggered a self preservation response and shut it self down. Either that or the jump in voltage destabilised the feed rails for the CPU and mobo, which would also have the same effect.

 

[The Pentium Guy]

What exactly do you mean by grounding yourself to the case?

 

[DCypher]

I believe that it will NEVER hurt it from touching the case. This is in essence a FARADAY CAGE, hence, when you touch it, all the the electricity coming from you will travel to the very outsides of the case. It's the same reason why you are safe in a car during a lighting storm, because if you get hit, all the shock goes to the outside of the car. Gotta love Michael Faraday.

 

[kcthomas]

i think power supplies usually connect the ground to the case. ie, the ground wire coming from the wall is thus tied to the case of the power supply. the case of the power supply screwed into the case of the computer so your case is connected to ground. touching the case would not harm the insides.

 

[SuperTool]

If I am not mistaken, in most if not all appliances with metal enclosures, the enclosure is connected to the third wire in the plug, which is the ground. That is to protect the user from shock more than anything.