ESD: Truths, myths, and flat out lies

In our class (that I have to take every single year) shows a chart of common materials in a manufacturing environment. Some are VERY capable of generating ESD, while others are not. The chart showed that if you took 2 pieces of styrofoam, rubbed them together, instant ESD. 2 pieces of wool, instant ESD. 2 pieces of glass, nothing, 2 pieces of wood, very little, if any at all.
 
I think you're confusing the term "ESD" with "static charge".

Let's suppose that you rub two packing peanuts together. They're usually made of polystyrene. Which one develops a positive charge, and which one develops a negative charge? Which one is gaining electronics, and where are they coming from?

If they're like materials, why is only one of them giving up electrons, and only one of them attracting free electrons?
 
SarverSystems said:
In our class (that I have to take every single year) shows a chart of common materials in a manufacturing environment. Some are VERY capable of generating ESD, while others are not. The chart showed that if you took 2 pieces of styrofoam, rubbed them together, instant ESD. 2 pieces of wool, instant ESD. 2 pieces of glass, nothing, 2 pieces of wood, very little, if any at all.
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Simply put, ESD stands for ElectroStatic Discharge. When talking about ESD in the context of computers, ESD can only occur when electricity is Discharged from one place to another. Just rubbing things together to build up a charge is not ESD.

You see when you rub two non-conductive materials together, sometimes electrons will be pulled from one material to the other. This changes the "charge" of the material. The one with additional electrons is considered to be negatively charged and the one that lost electrons is positively charged. Rubbing two identical items together however will usually not produce much of a charge.

Now when you take an object (such as your skin) that has built up a large static charge, and you touch it against something conductive that's at a different potential, the extra electrons will be attracted to the lower potential and will rush to try and reach it. This sudden moving of electrons from one object to another (in this case, your computer components) is called ESD.
 
I'm surprised to see the errors in the first post haven't been corrected yet, even though this is a sticky.

Meanwhile, the ESDA has announced their 2007 symposium: PDF program
 
I use the ESD foam from all the motherboards I've had all through the years as ghetto sound dampeners/ to hide cable behind. It comes in contact with the edge of my mobo slightly.

Should I reconsider?
 
Impulse said:
Hey, there's actually an upside to living in this horrid humidity? Who would've thought...
tongue.gif
But seriously now, good write up, a heads up for many I'm sure.
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Tell me about it, I live in Florida, just a few days ago after a tropical shower humidity was at 90% and it was 102 degrees out side. I was just standing in the shade and started sweating.:p Anyway, I don't ever use the static wrist bans anymore. Maybe I should rethink that.

Edidt: @ TomMe, I use cotton balls to remove thermal paste, and have nto had a problem yet.
 
TomMe said:
How do you guys remove thermal compound from a CPU with ESD in mind?
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Go to Radio Shack or other electronics store and get yourself a static mat kit. It will usually consist of a large flexible mat, a cord with a wrist attachment, and another cord you can plug into a wall outlet ground.

Gives you a decent ESD resistive work area at an affordable price. ;)
 
Already have that DejaWiz. But I was thinking that rubbing paste off of the CPU might produce some static discharge.

I've always used paper towel and isopropyl alcohol, not sure if that's healthy for the CPU.
 
TomMe said:
Already have that DejaWiz. But I was thinking that rubbing paste off of the CPU might produce some static discharge.

I've always used paper towel and isopropyl alcohol, not sure if that's healthy for the CPU.
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If you've placed yourself and your cpu at the same potential as ground with the mat, then using a paper towel will be fine since it too will be at the same potential.
 
Trepidati0n said:
[snip]

However, the reason why most consumers don’t “appear” to have ESD problem is because, in our own homes, we are naturally “ESD smart” when working with electronics w/o even trying.

[snip]

However most times when we working with electronics we “touch” the case first or “touch” the edge of the board/component first. Since we touch something that is low impedance we quickly “share” the energy with the item touched and thus “prevent” a large voltage differential on something that is sensitive.

Remember, in order to create ESD damage you MUST move that energy in a differential fashion through something that is sensitive to it.

[snip]

Therefore all the ground strapping and mats and bags and stuff are good if you working in an environment where you can’t control the flow of energy consistently or working with millions of dollars in parts per day. However, for the average Joe in his house…if you stop moving and touch your case…you have covered a huge portion of what you need to worry about.

Easy rules of thumb:

1. Always touch your case before touching the electronics
2. Try to keep parts in ESD bags
3. Don’t touch parts by their pins (grab on edges)

If you do that….as a consumer, you have done enough IMO.

[snip]

In short the myth people are wrong and right…and the paranoid people are wrong and right.
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I was one of the ones who characterized ESD as more of a myth. IMO, this post is one of the better explanations of ESD. The problem I have with ESD is the hysteria. As this post shows, you almost have to try and ruin something with ESD. And my guess is that when something stops working without explanation, many people just blame ESD. Yes, small gnomes broke in and sole my socks...hey, it's possible

If you want to spend a few $ on some ESD equipment, fine. A mat and a wriststrap are not too expensive. But I've seen (with my own eyes) rooms made of copper and rooms with no ground potential at all, costing amazing amounts of money trying to avoid ESD.

Anytime people talk about ESD, I wish they did so like in the post above. ESD exists, it's a risk, but it's extremely low. Don't lose sleep or large amounts of cash over it. Limited precautions bring the already tiny risk to near zero.
 
Sorry if it's been answered before, but how come most memory manufacturers have stopped using ESD protection bags, and are just using hard plastic around their modules?

Is this really fine:confused:
 
Edvuld said:
Sorry if it's been answered before, but how come most memory manufacturers have stopped using ESD protection bags, and are just using hard plastic around their modules?

Is this really fine:confused:
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because they don't care if you damage your memory with ESD lol...

ESD is real.. but so long as you're not an idiot (I.e. rubbing your feet in carpet while handling eletronics), you should be ok
 
Edvuld said:
Sorry if it's been answered before, but how come most memory manufacturers have stopped using ESD protection bags, and are just using hard plastic around their modules?

Is this really fine:confused:
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From what I've been told (and I could have been told wrongly), those packages are actually static resistant. Like I said, I don't know if that is right or wrong, but that is what I've been told.
 
protias said:
From what I've been told (and I could have been told wrongly), those packages are actually static resistant. Like I said, I don't know if that is right or wrong, but that is what I've been told.
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i've never heard that.. as far as i know they're just being cheap
 
RancidWAnnaRIot said:
because they don't care if you damage your memory with ESD lol...
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Of course they do. When it happens, you make a return to a retail or RMA the part directly, and that cuts into their already thin profit margin.
 
c'mon guys.....i've been building machines on my carpet for years!!!

*pushes pile of failed devices out of view*

.......goin and getting people all worked up like that
 
hi

if i understand correctly, PSUs typically ground the conductive PC case. if i will use a cardboard box as my case, which is nonconductive, would it cause any problems related to EDS/shocks/electricity/etc?

also, if i won't use screws to connect the components anywhere, and just put them "on desk", would the possible free movement of these parts (due to HDDs/fans/etc) make them charged? either this is an absurd thought or then i would be better using tape/glue to make the components stand still.
 
It'll work as shown by many computers already built that way.

The way i see it all the components have a ground wire anyway and are grounded that way.

That's not to say that if you move a piece of equipment it won't be effected by ESD.
 
It might work. It's certainly not the right thing to do, though.
 
That's why there's at least one ground for each power wire. Look at your ATX connecter and count how many grounds are present. Each one works with 1 power wire.
 
mikeblas said:
I'm surprised to see the errors in the first post haven't been corrected yet, even though this is a sticky.
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LOL yeah. This has got to be one of the most potentially mis-informed, wandering topic threads that could possibly qualify for sticky status. Great entertainment value though :)



kinglerch said:
The problem I have with ESD is the hysteria. As this post shows, you almost have to try and ruin something with ESD. And my guess is that when something stops working without explanation, many people just blame ESD.
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Word :) No disrespect intended, but a lot of the posts here like this one are excellent examples of that:

if i won't use screws to connect the components anywhere, and just put them "on desk", would the possible free movement of these parts (due to HDDs/fans/etc) make them charged?
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Agent420 said:
This has got to be one of the most potentially mis-informed, wandering topic threads that could possibly qualify for sticky status.
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Yeah, and the hits just keep on coming. For example:

SarverSystems said:
That's why there's at least one ground for each power wire. Look at your ATX connecter and count how many grounds are present. Each one works with 1 power wire.
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Except, on ATX power supplies, there's not one ground line per supply line.

What's your point, anyway? What is why?
 
OK. Tech support here for a gaming case manufacturer. I often get ESD calls from Arizona customers, and with winter rolling in, I expect even more. Basically these emails are stating that it is the fault of the case that it shuts down upon touching the front panel. Now for the record, I am A+ certf'd, but my actual field of study is computer networking. Many times customers will email with some lengthy correspondence that delves into into the realm of electronics, which goes over my head. But even with their knowledge, the tone of their emails usually indicates that they are not sure of the reason why, yet they still scream "design flaw".

My question is, is it accurate to say that it is a design flaw that causes the PC to shutdown/restart even though they are knowingly in a low humidity environment? Should a PC case be immune to ESD no matter what environment it is in? I am asking because I simply do not want to provide inaccurate info either way. Thanks
 
There's no way to ESD proof a pc simply by case design - the real issue is the motherboard, or at least any electronic interface to the outside world.

Cases are often grounded, but what other steps could you take? You still have open usb ports, audio plugs etc that would be potential access points. ESD protectiion is typically provided by some proactive circuit design.

It is possible to ESD harden an elecrtonic device... Most commercial equipment from dishwashers to slot machines incorporate various design methods that are substantially better than the common pc. In their defense, most pc's and the components that comprise them are much less vulnerable than a lot of people give credit for.

Note there is a big difference between the common complaint of esd potentially triggering a shutdown signal, and esd damage.
 
It's entirely possible that it's a design issue. An ESD-charged person can have, on a carpeted floor on a dry day, tens of kilovolts on themselves. If they touch the power button of your company's case, it's possible to get an arc going through the power button, reaching the actual contacts of a switch and creating a discharge path through the MB's front panel connector.

The company I work for, in a few products, uses metal dome switches mounted behind a flexible plastic overlay. There's a sheet of foil embedded inside the overlay which is there solely to provide an ESD discharge path, so that a static-charged user doesn't blow the thing up. We've had this tested by one of the certification agencies - they use a metal "finger" on a fiberglass stick connected to a grounded capacitor, which they charge up to a few KV. They then start touching various parts of the equipment to see what happens. We passed. :D


d4rk5un said:
OK. Tech support here for a gaming case manufacturer. I often get ESD calls from Arizona customers, and with winter rolling in, I expect even more. Basically these emails are stating that it is the fault of the case that it shuts down upon touching the front panel. Now for the record, I am A+ certf'd, but my actual field of study is computer networking. Many times customers will email with some lengthy correspondence that delves into into the realm of electronics, which goes over my head. But even with their knowledge, the tone of their emails usually indicates that they are not sure of the reason why, yet they still scream "design flaw".

My question is, is it accurate to say that it is a design flaw that causes the PC to shutdown/restart even though they are knowingly in a low humidity environment? Should a PC case be immune to ESD no matter what environment it is in? I am asking because I simply do not want to provide inaccurate info either way. Thanks
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My education has been more on the Cyb side of things rather than EE, so I'm a little fuzzy on my EM theory and circuit design practices:
1) Would I be correct in assuming that holding a board by it's edges is significantly safer than holding the (solder-mask coated) surfaces of the PCB, and that any traces between the layers that may be exposed will be ground traces anyway?
2) Is it safe to place masking tape over exposed contacts on sensitive components (e.g. the land grid array on a s775 CPU)? My intent is to use strips to cover the read of the CPU whilst lapping. I know that sellotape/scotch-tape exhibits triboluminescence when peeled due to charge separation, but I have no idea if the charge persists, or if masking tape also exhibits this effect.
Or maybe I'm just being paranoid. As I said, I've never been too hot on my EM theory.
 
Yes, it's a little safer to hold the board by the edges. Inducing an ESD event into ground isn't any safer than injecting it anywhere else in the circuit, though. When the board is off, ground is not attached to anything and is just another trace.

If you're lapping the part, I guess you don't really care about its safety anyway, and the tape is the least of your worries.
 
EdZ said:
My education has been more on the Cyb side of things rather than EE, so I'm a little fuzzy on my EM theory and circuit design practices:
1) Would I be correct in assuming that holding a board by it's edges is significantly safer than holding the (solder-mask coated) surfaces of the PCB, and that any traces between the layers that may be exposed will be ground traces anyway?
2) Is it safe to place masking tape over exposed contacts on sensitive components (e.g. the land grid array on a s775 CPU)? My intent is to use strips to cover the read of the CPU whilst lapping. I know that sellotape/scotch-tape exhibits triboluminescence when peeled due to charge separation, but I have no idea if the charge persists, or if masking tape also exhibits this effect.
Or maybe I'm just being paranoid. As I said, I've never been too hot on my EM theory.
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Use the black plastic cover that came with your CPU. That should do just fine.
 
Metal buttons/switches really should be grounded to the case. I assume this one wasn't? It seems to have discharged via another path, killing the LED in the process :(
 
yeah.. it's in a wood/mdf case I built, and the power button is mounted on an acrylic face plate.
 
LEDs are not ESD-sensitive devices. Are you sure the LED is dead, and not the output on the motherboard?
 
It might have transferred into the motherboard and killed the output on that end. But regardless, the LED doesn't light up anymore. I don't feel like taking it apart to test it.. I'll just leave it as-is.
 
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