pcgeek11
Lifer
- Jun 12, 2005
- 22,350
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Well you guys are hitting all around the issue involved with ESD but some of you are missing the key factor here.
Lets say you have the PC on the carpet which doesn't conduct, You are touching the case which puts you both at the same voltage potential as long as you don't touch anything else you will be fine. But when you pick up a tool or touch anything else ( which could be at a different voltage potential ) you are running the risk of sending dangerous currents through sensitive components. If you have the PC on a mat and your tools on a mat and you have a wrist strap on connected to the PC Chassis everything is all connected to the same voltage potential there will be no current flow. And no danger to electronic components or you.
Pulling a strip of clear tape off a roll can and does generate upwards of 10,000 volts potential of static electricity. So scooting your big @ss across the carpet can do it too.
I know we all do not have ESD workbenches set up in our houses... Leaving the power supply plugged in and off will give any static a place to go. There are no dangerous voltages coming out of the power supply that will injure a human. and none if the power supply is off. If you just connect yourself to the PC Chassis with a ground strap with no ground (earth) in place and you reach over and grab a screwdriver by the handle the metal of the screwdriver could be at a much higher voltage potential than the PC or yourself and could in fact send a dangerous current through the electronics of the PC. Even if the component is not fried immediately it usually shortens the life span of that component.
I also have done work without taking the proper precautions and gotten away with it, The OP asked what is the PROPER way to use a ground strap, not how do you screw up the electronics.
Take a Class in ESD or at least google it.
pcgeek11
Lets say you have the PC on the carpet which doesn't conduct, You are touching the case which puts you both at the same voltage potential as long as you don't touch anything else you will be fine. But when you pick up a tool or touch anything else ( which could be at a different voltage potential ) you are running the risk of sending dangerous currents through sensitive components. If you have the PC on a mat and your tools on a mat and you have a wrist strap on connected to the PC Chassis everything is all connected to the same voltage potential there will be no current flow. And no danger to electronic components or you.
Pulling a strip of clear tape off a roll can and does generate upwards of 10,000 volts potential of static electricity. So scooting your big @ss across the carpet can do it too.
I know we all do not have ESD workbenches set up in our houses... Leaving the power supply plugged in and off will give any static a place to go. There are no dangerous voltages coming out of the power supply that will injure a human. and none if the power supply is off. If you just connect yourself to the PC Chassis with a ground strap with no ground (earth) in place and you reach over and grab a screwdriver by the handle the metal of the screwdriver could be at a much higher voltage potential than the PC or yourself and could in fact send a dangerous current through the electronics of the PC. Even if the component is not fried immediately it usually shortens the life span of that component.
I also have done work without taking the proper precautions and gotten away with it, The OP asked what is the PROPER way to use a ground strap, not how do you screw up the electronics.
Take a Class in ESD or at least google it.
pcgeek11
The current will flow from your body to the chassis. There is no sensitive component in that path. The chassis has a significantly higher capacity for charge compared to anything else connected to it (individual components). Earth has an even higher capacity. That is why it is preferred. But, you don't always have access to it. How would one ground himself/herself (to earth) on the space-station or inside a submarine or on a plane?
Of course if you connect yourself to a transistor gate instead of the chassis, what you describe will happen. The current will pass through the transistor and could fry it and having the chassis connected to Ground is not going to make it any better in that case.
This thread explains why most compnaies rate PC techs in a lower pay grade than janitors, and rightly so.
The most sensitive computer components to electrostatic discharge, like RAM, cannot be harmed by a static discharge once they are properly slotted because you have too much conductive area and hence no bridge to jump. You've all been whacked by touching a door knob after walking across a carpet (some more than others). Now walk across that same carpet while holding a metal fork and touch the doorknob with the fork, and note how you don't feel a shock because the current has been distributed via the conductive area of your skin to metal. Electronic components get damaged by static discharge when thousands of volts instantly propogate across a bridge that's only a few molecules wide. The proper way then to wear a wrist strip is around your neck so you can hang yourself with it and give another Darwin Award winner a job. REAL computer techs periodically touch the case when working on / installing components, and that's all that's necessary.
I've worked on PC's in older buildings with faulty coax connections that have blown the screwdriver out of my hand when I toughed the case, and been knocked to the floor by broadband connections in older houses. Trust me, a wrist strap isn't going to help those scenarios other than make your fillings rattle.
The main cause of electronic failure with computer components is simply crappy stepping circuits on MB's and defective chinese resistors and capacitors. That's the real culprit.
RadiclDreamer
Diamond Member
- Aug 8, 2004
- 8,622
- 40
- 91
Couldnt have said it better myself, ive been doing PC/Networking all the way from a bench tech to IT MGR to Director of IT ive not once used a static mat or strap and have yet to fry a part.
pcgeek11
Lifer
- Jun 12, 2005
- 22,350
- 4,973
- 136
Well this thread proves only one thing:
Opinions are like @ssholes, everybody has one and most of them stink.
I have been working in electronics since 1970, and just because you haven't seen it happen doesn't mean that it doesn't. Why do you guys/girls think thousands of dollars are spent on ESD protection through the last 25 years? Just because Corporations love to spend money? Hardly. One of the few people in this thread that sounds like they have a clue is Navid even though he is incorrect on some aspects of this topic.
And for spikespiegal, RadiclDreamer
They must pay janitors pretty d@mn good where you are ( ie in excess of six figures )? You don't have a clue what you are talking about. You seriously need to study a bit before you pass the ignorance to others.
Do something productive and read this:
http://www.phys.cwru.edu/courses/p203/r...ure.pdf#search=%22ESD%20precautions%22
The OP asked what the CORRECT use was, not for your backwards opinion.
pcgeek11
Opinions are like @ssholes, everybody has one and most of them stink.
I have been working in electronics since 1970, and just because you haven't seen it happen doesn't mean that it doesn't. Why do you guys/girls think thousands of dollars are spent on ESD protection through the last 25 years? Just because Corporations love to spend money? Hardly. One of the few people in this thread that sounds like they have a clue is Navid even though he is incorrect on some aspects of this topic.
And for spikespiegal, RadiclDreamer
They must pay janitors pretty d@mn good where you are ( ie in excess of six figures )? You don't have a clue what you are talking about. You seriously need to study a bit before you pass the ignorance to others.
Do something productive and read this:
http://www.phys.cwru.edu/courses/p203/r...ure.pdf#search=%22ESD%20precautions%22
The OP asked what the CORRECT use was, not for your backwards opinion.
pcgeek11
Not necessarily true. Simply connecting a device to a board is no guarantee that it will be protected from ESD. In some cases, this has been proven to make the device more sensitive to damage.
At any rate, plugging a module into a PCB no means that you have loads of extra traces which are able to channel a static discharge into your module.
It wouldn't surprise me - but that doesn't mean that ESD isn't a significant problem. It's certainly less of a problem as chips now incorporate improved protection circuits - but as CPUs and other devices become faster, and on smaller processes, then it's likely that sensitivity to ESD will increase.
I've been building my own computers for about 9+ years now and have never used a wrist strap or really even given much though to ESD. No problems so far and I don't think the minute chance of damaging something with an ESD is worth the hassle of doing the whole wrist-strap thing. Of course, this is my mostly uneducated view on the dangers of ESD while working on a PC.
Good thread, it's pertinent as I'll be building a new machine this weekend. In previous builds, I've always done what others have mentioned and that is to simply keep *some* part of my body touching the metal portion of the PC chassis at all times while touching and working with the various components. For my new build, I decided to purchase an anti-static wriststrap to 'do it right.'
The OP asked for the 'proper' way to use a wriststrap, and I feel that that information has been provided. The real question is, however, is proper use of the the wriststrap adequate enough to prevent ESD in order to protect the components from damage during installation and upgrading, and also to prolong their life. One of the things mentioned previously is that damage can occur without knowing about it. IOW, you can damage a component, not to the point of ruining it, but enough to shorten its life.
That's the part I'm MOST concerned about.
The OP asked for the 'proper' way to use a wriststrap, and I feel that that information has been provided. The real question is, however, is proper use of the the wriststrap adequate enough to prevent ESD in order to protect the components from damage during installation and upgrading, and also to prolong their life. One of the things mentioned previously is that damage can occur without knowing about it. IOW, you can damage a component, not to the point of ruining it, but enough to shorten its life.
That's the part I'm MOST concerned about.
pcgeek11
Lifer
- Jun 12, 2005
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- 136
Another very educational site here of the real facts. For those that want to learn the real facts.
http://www.esda.org/aboutesd.html
pcgeek
http://www.esda.org/aboutesd.html
pcgeek
So the most important part of a wrist strap is the resistor then? Because what you touch can be at different potential then the case you are strapped to, the resistor in the strap causes the current transfer to be slow enough not to cause damage? So that is why a connection to an "earth" ground is not necessary?
A connection to a common point is necessary. However, such connection must be ideally made through a resistor for limiting the current. The most convenient common point is ground because it is almost everywhere and it has an extremely high electrical capacitance.
What is special about the metallic part of a PC case is that every component in the PC is already connected to it through the motherboard ground plane.
You may then ask "why do you say to touch the case, where is the resistor then"?
The advice is to touch the case before touching anything else and do it frequently. So, if your body and the case are at different potentials, you bring your body and the case to the same potential by touching it. The current could be too high for a sensitive transistor. But, the current flows while you are not touching anything else. So, such current does not flow through a sensitive component. You are basically dumping charge into (from) the motherboard ground plane. The ground plane is the point of reference. Changing the potential of the ground plane changes the potential of everything (transistors etc.).
Altitude is always the best analogy.
Think of a platform the size of a Football stadium that could move vertically (motherboard ground plane voltage).
Think of people standing on this platform (ESD-sensitive components soldered to the motherboard).
Think of lifting only one of those people 1000 feet in the air with the platform still on the ground (you being charged touching a transistor before touching the case). This could be fatal!
Now, instead, think of the entire platform moving up 30 feet with all those people standing on it (you being charged touching the case before touching anything else). This, in itself, is not fatal. Of course, if one of those people jumps off of the platform, we will have a problem (someone else who is not charged touching one of the components on the motherboard before touching the case)!
The shortcoming of this approach is that if you develop ESD while you are touching a component, it could be at risk.
While building and working on a PC? Is there an interpretive dance routine you'd like to share with us?
pcgeek11
Lifer
- Jun 12, 2005
- 22,350
- 4,973
- 136
After reading this thread through once again...
It is obvious that the first thing nearly everybody recommends is "perform a memtest ". It seems that probably the biggest problems seen are memory failures on this board. I have never had a stick of RAM or chip fail me since the 8086 days... and I use ESD protection.... could there be a link here? I think so.
Current can flow from you to the component or from the component to you either way.
You don't " Develop ESD " (Electro Static Discharge) you develope th static charge or provide a discharge path.
" The current will flow from your body to the chassis. There is no sensitive component in that path. " Every component is in that path, the chassis in common to everything, and current can flow either direction.
" The most sensitive computer components to electrostatic discharge, like RAM, cannot be harmed by a static discharge once they are properly slotted because you have too much conductive area and hence no bridge to jump. You've all been whacked by touching a door knob after walking across a carpet (some more than others). Now walk across that same carpet while holding a metal fork and touch the doorknob with the fork, and note how you don't feel a shock because the current has been distributed via the conductive area of your skin to metal. Electronic components get damaged by static discharge when thousands of volts instantly propogate across a bridge that's only a few molecules wide. The proper way then to wear a wrist strip is around your neck so you can hang yourself with it and give another Darwin Award winner a job. REAL computer techs periodically touch the case when working on / installing components, and that's all that's necessary. " Stupid statement of the year award.
" Couldnt have said it better myself, ive been doing PC/Networking all the way from a bench tech to IT MGR to Director of IT ive not once used a static mat or strap and have yet to fry a part. " Companies usually advance people above their level of Incompetence.
" Of course, this is my mostly uneducated view on the dangers of ESD while working on a PC. " This is at least an honest statement.
Touching the case does help prevent ESD, but it is not the end all answer. You need a common potential for all components, tools, the PC, and yourself.
pcgeek11
It is obvious that the first thing nearly everybody recommends is "perform a memtest ". It seems that probably the biggest problems seen are memory failures on this board. I have never had a stick of RAM or chip fail me since the 8086 days... and I use ESD protection.... could there be a link here? I think so.
Current can flow from you to the component or from the component to you either way.
You don't " Develop ESD " (Electro Static Discharge) you develope th static charge or provide a discharge path.
" The current will flow from your body to the chassis. There is no sensitive component in that path. " Every component is in that path, the chassis in common to everything, and current can flow either direction.
" The most sensitive computer components to electrostatic discharge, like RAM, cannot be harmed by a static discharge once they are properly slotted because you have too much conductive area and hence no bridge to jump. You've all been whacked by touching a door knob after walking across a carpet (some more than others). Now walk across that same carpet while holding a metal fork and touch the doorknob with the fork, and note how you don't feel a shock because the current has been distributed via the conductive area of your skin to metal. Electronic components get damaged by static discharge when thousands of volts instantly propogate across a bridge that's only a few molecules wide. The proper way then to wear a wrist strip is around your neck so you can hang yourself with it and give another Darwin Award winner a job. REAL computer techs periodically touch the case when working on / installing components, and that's all that's necessary. " Stupid statement of the year award.
" Couldnt have said it better myself, ive been doing PC/Networking all the way from a bench tech to IT MGR to Director of IT ive not once used a static mat or strap and have yet to fry a part. " Companies usually advance people above their level of Incompetence.
" Of course, this is my mostly uneducated view on the dangers of ESD while working on a PC. " This is at least an honest statement.
Touching the case does help prevent ESD, but it is not the end all answer. You need a common potential for all components, tools, the PC, and yourself.
pcgeek11
I still don't get any of this stuff. Say you have a fancy ESD safe area tied to earth ground. Next your new ram comes in from NewEgg, let us say that it is at a level of charge other then earth ground. Wrist strap or not, if you touch it it will get shocked.
What damages a component is a large current flowing through it.
Let's say your body is at 0 Volts and you are connected to ground through a wrist strap. Don't forget about the resistor in the wrist strap.
Let's say the RAM is at 500 Volts.
When you touch the RAM, The 500-Volt voltage will be across the combination of RAM + you + the wrist strap resistor to ground. The current flowing through this chain from the RAM to ground will be equal to 500V divided by the overall resistance. The wrist strap resistance is high (about 1 Mega Ohms). Your body has an electric resistance of about 1 Mega Ohms as well. This results in a low current, which cannot harm the RAM.
The RAM voltage will drop to zero due to its electrostatic charge flowing to ground.
Would there be any advantage to wearing latex gloves (like what a doctor/dentist wears)? Maybe in terms of preventing skin oils from building up on the components, or would the rubber latex be less 'conductive' than bare flesh? Just a thought I had.
I like living life on the edge, I never use one and I take my computer apart all over the place on a variety of surfaces. Have never had a problem but I guess it will catch up to me one day.
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