http://en.wikipedia.org/wiki/Ground_plane
From that link:
Printed circuit boards
A ground plane in PCB assembly is a layer of copper that appears to most signals as an infinite ground potential. This helps reduce noise and helps ensure that all integrated circuits within a system compare different signals' voltages to the same potential.
Often, the ground plane is shorted to the frame as well. I expect the bracket of a graphics card, that you use to attach (screw) it to the case, is connected to the card ground plane.
So, I always hold a graphics card by holding that metallic frame (bracket).
One does not need to get grounded!
You have to be at the same voltage as what you touch. Otherwise, there could be a spark.
I would also place it on an ESD bag. A cardboard can cause static charge to be developed when touched.
If anyone tells you that one must be grounded in order to safely work on an electronic equipment, ask them to describe how an astronaut grounds himself/herself in space for that purpose!
Got it. Seems obvious if the pc is already built. I assume that it's really static potential differential.
What if there's no chassis? For example, you're building a pc with parts ordered, some have been delivered but the case and psu haven't. You have the bag with the mb in your hands. What else should you touch before you reach into the bag?
I should have guessed that somebody would come up with kitsch like this. It doesn't look very secure if the pc is ever jolted.
Anti-static
http://i259.photobucket.com/al...avid200/AntiStatic.jpg
Aluminum foil
http://i259.photobucket.com/al...02/Navid200/AlFoil.jpg
I am yet to see a motherboard anti static bag that is conductive!
By all means, if you have an anti-static bag that is conductive, do not put the motherboard on it.
You might have misread - there's a lot on that page.
"Power Supply making too much noise? Vantec Power Supply Vibration Dampener Kit can fix that! The general cause of excess noise of the power supply is due to vibration from within. What the vibration dampener kit does is absorb the vibration produced by the power supply with its' special ultra-light Silica Gel material while simultaneously adds extra protection to your power supply! And don't worry about what size you should get, one size fits all standard ATX power supplies."
And the first warning bell should have been Vantec - and then an ad replete with lots of exclamation points.
mindless1
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That product will usually ground case to PSU still because the metal screws contact the hole and outer skin of the case, and the threaded portion of the PSU case.
Even without this factor, the PSU ground power leads are one primary path if PSU casing were insulated from system case. There are lots of ground paths in a PC.
Consider for example that if you take a multimeter set to continuity (or resistance) mode and put one probe on the assembled-system case and the other probe on the PSU AC socket's ground pin, you should find it continuous. Same with a hard drive, it's (threaded) frame holes are usually continuous to it's negative power contact. Same with a video card as Navid mentioned, or other cards also typically have ground plane connected to case bracket. Motherboard standoffs also connect motheboard ground plane to case. The general rule is that if a products mounting is metal and can be grounded, it is.
Very likely I am misunderstanding your comments.
The PSU-related product on that page is a flexible surface that you place between your PSU and your case. Then, you tighten the screws to install the PSU. Except that you do not tighten the screws so much to completely compress the flex material to its limit.
Now, vibrations in the PSU (caused by its fan) will be somewhat absorbed by the flexible material instead of being transferred to the case.
I don't see anything wrong with that concept!
The case could act as a loud speaker. So, you would want to isolate it (mechanically) from any moving part.
Ok everybody. Take a good look at the advertisement. Notice the grommets? I believe they are intended to be used _instead_ of screws. This is why I questioned stability.
And now for the mea culpa. I looked at the ad again and see that the grommets pictured are not for this product. Fucking misleading ad's.
I still think it's kitsch.
And now for the mea culpa. I looked at the ad again and see that the grommets pictured are not for this product. Fucking misleading ad's.
I still think it's kitsch.
mindless1
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If you only write ground it is reasonable to state one must be grounded to safely work. Ground just doesn't necessarily mean earth ground, it means electrical system ground which is the same concern for us or astronauts. Being grounded to an earth ground to which the system ground is not connected is not always effective protection.
But, that is my point!
What matters is the point of reference.
The ground plane of the motherboard could also be the point of reference. If everything is at the same voltage as the motherboard ground plane, including the operator, there will be no spark, even if they are all at 20,000V with respect to Earth (the third connector of the outlet).
I was referring to those who state that you either have to be connected to the third connector of an outlet or else you take the risk of ESD damage.
mindless1
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The pictured bag is only one type probably mean to minimize triboelectric static generation and a metal-in(side) construction which would require a higher voltage than a multimeter produces to conduct though the plastic, unless something with sharp pointed parts (like leads from capacitors on the motherboard) where to pierce it).
Many are conductive, a common example is the type which is clear and has black lines criss-crossing all over it which look not exactly but a bit like this.
The issue is which type of ESD protection the bag tech uses. See the following link, "Types of ESD Bags" for different methods of protection.
Once upon a time ago, I used to keep an antistatic bag on a table I set up systems on to test. Eventually I came across boards that wouldn't even POST because the bag was conducting across areas of the board back. Such bags have quite high resistance so the issue is how sensitive the circuit is, and how close together two conducting contacts on the back are.
mindless1
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A magazine (or two beside each other for large boards, or two of uneven height when the board has irregularities on back like heatsink mounting studs of significant height) just tall enough that it gives the card slot brackets clearance off the table.
I also have a nice piece of MDF I prefer but it's larger and doesn't allow different height parts on the back like two magazines would. I suppose I could plane down a 2nd piece of wood but that's more work than I care to do.
They have no purpose related to ESD and I usually don't take ESD precautions with my own parts, but do have a wrist strap for when something is valuable or ESD events have been observed. I have scrambled a video card bios for certain due to this attitude, but fortunately it took a new bios ok and my position is still one of being too lazy to bother with ESD prevention on cheaper parts or when it seems unnecessary.
You may have a 1 Mega Ohm resistance on a surface and say that it is conductive. That is what is considered conductive in an ESD sense, where you deal with kilo Volts.
But, if you have only 3V across it, it will only conduct 3uA!
I am curious if you have any reference that shows the resistive value of the bags you are talking about.
Now that's something I wouldn't use. I've felt static buildup on some of the high gloss ones. I've tried 1/2" plywood but felt that the pins in the solder joints on the bottom could be bent/loosened if much pressure was applied. So for the last couple of years have used unpainted cardboard successfully.
mindless1
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Yes 3uA isn't much but the two contacts may be closer, lowering resistance, and may be sensitive to signal level differences.
I'd imagine there are references out there somewhere but instead I just grabbed a bag here that came with some motherboad (can't recall what make or model). It does not have any spec labeling on it unfortunately, measures roughly 1.2 MOhm/inch across medium thickness line.
Great! That's what I thought.
If you measure the resistance between your left hand and right hand by grabbing each probe of the meter hard, you will see a resistance less than that. Your body is more conductive than that ESD bag!
Such a high resistance can never cause any damage to the motherboard.
mindless1
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I don't slide the board on the magazine nor flip through it, and we have a controlled humidity level always above 30%. I've never found a magazine problematic but prefer MDF or pine when feasible due to being more solid, yet less so than plywood, plus I sand down and lightly oil various boards for other project board uses and find my generic construction C grade plywood doesn't reach as nice a finish. I thought about using some burlap covered corkboard but I have only one sheet of it and want it whole for another use.
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