a matter of static

Our "pub" where you can post about things completely Off Topic or about non-silent PC issues.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
minibeardeath
Posts: 31
Joined: Fri Apr 06, 2007 9:25 pm
Location: walnut creek, CA
Contact:

a matter of static

Post by minibeardeath » Tue Apr 10, 2007 9:58 pm

I live in warm sunny northen california, but im not bragging. the problem with warm sunny california is the warm sunny part because warm sunny seems to be interwoven with :evil: :evil: :evil: :evil:STATIC :evil: :evil: :evil: :evil: . thats just the build up

my even bigger problem is one of hair and jewelry. i am a guy with long staticy hair and a brand new silver eagle scout ring. i am definetly going to get one of those antistatic bracelets (even though ive never done any damage to any of my machine due to static) and i was wondering first how bad can static be to a computer part (im talking extremely high static charges [like ive had static jump from my finger to the wall over an inch gap (my arm was numb for 30 min :lol: )]) second how well do the bracelets work and third does wearing my ring while working on my comp lead to a higher risk of damaging static shock????

thanks in advance

Plissken
Friend of SPCR
Posts: 235
Joined: Tue Dec 19, 2006 6:22 pm
Location: Seattle

Post by Plissken » Tue Apr 10, 2007 10:12 pm

If the shock is enough to numb your arm for 30 min., I'm sure it can do a lot of damage to sensitive electronics! ;)
Bracelets work well. A ring won't add any more risk than your fingertip since they'll be at the same potential.
There was a thread here a few weeks ago on the risks of ESD that should offer some insight.

nzimmers
Posts: 271
Joined: Mon Dec 04, 2006 6:13 pm

used to be

Post by nzimmers » Tue Apr 10, 2007 10:14 pm

used to be pretty common for people to be paranoid about static, I remember I bought a few motherboards from "treasure chest computers" way...way back and they included a anti-static wrist band with every purchase.

yes, static can discharge thousands of volts, but the amperage is so tiny. I am sure there are some that may still cling to the old belief that static is dangerous to computer components, but if some component fails due to a static discharge from a human then it was a piece of * to begin with.

all you have to do is make sure you touch some piece of metal before you start reaching in you case, that will dischage anything you have built up combing that nice long hair of yours ;)

[EDIT]

I just did some casual research.....my god there's so much sh*t on the internet that's wrong.....it's crazy

here's quote from a post on HardOCP that was linked from another thread on ESD from SPCR:

"ESD damage can occur to static senstive devices with as little as 1 volt of electricity. Most devices need about 100 volts before they are damaged beyond repair. People can't feel the static discharge until about 2,000 volts and higher. So just because you didn't feel the zap, doesn't mean it didn't occur."

wrong, I wish I could find the guy that wrote the above cr*p and jolt him with 1 volt with 200amps and see what he feels (actually he wouldn't feel anything cause he would be dead from the instantanious cooking his body would suffer)

according to this genius from Hardocp, I shouldn't feel the 120volts from the power outlet in my kitchen right?

it's false everyone, ESD is only for truly precise and sensitive electronic components and there's nothing in a computer case is precise and sensative to that extent (like internals of aircraft instruments) that's going to be damaged in anything but the most extreme cases of ESD

Sylph-DS
Posts: 223
Joined: Wed Apr 04, 2007 2:56 am
Location: The Netherlands

Post by Sylph-DS » Wed Apr 11, 2007 2:28 am

Nzimmers, you seem rather a bit of a skeptic. I can't say I agree with you. If it wasn't an issue, then why do you think manufacturers the world over wrap their products in anti-ESD baggies? Because the customer likes it? No, because there's a chance that if they don't the product is damaged and they'll have to give refunds.

Yes, the chance of an apocalyptic ESD is miniscule, but less destructive ones happen all the time. Just because your GFX card seems to work right, doesn't mean it won't fail when you put it in just the right situation. Often times all you damage in an ESD is for example one tiny piece of memory, meaning that the component won't fail untill exactly that piece of memory is called upon to do a certain thing, and then still it may not fail completely.

ESD may not be as dangerous as its sometimes put up to be, but it's definitely something you should think about.

nick705
Posts: 1162
Joined: Tue Mar 23, 2004 3:26 pm
Location: UK

Re: used to be

Post by nick705 » Wed Apr 11, 2007 3:01 am

nzimmers wrote: yes, static can discharge thousands of volts, but the amperage is so tiny. I am sure there are some that may still cling to the old belief that static is dangerous to computer components, but if some component fails due to a static discharge from a human then it was a piece of * to begin with.
The voltages generated in a static electricity buildup of this type (tribocharging) can reach tens of thousands of volts, and the peak current is often *not* insignificant - it just lasts for a vanishingly small period of time when the discharge takes place, so the total energy release is small and it doesn't fry you on the spot.

It can easily damage delicate electronic components though, or else the manufacturers could save a small fortune on antistatic packaging. You can easily prove it - get a nice new stick of Corsair Dominator PC2-10000 RAM, jump up and down a bit on a nylon carpet, and while you're in mid-air touch the RAM to a grounded central heating radiator.

Go on, I dare you...
wrong, I wish I could find the guy that wrote the above cr*p and jolt him with 1 volt with 200amps and see what he feels (actually he wouldn't feel anything cause he would be dead from the instantanious cooking his body would suffer)
Good luck trying to instantaneously cook a human body with 200 watts... :P

Trekmeister
Posts: 83
Joined: Wed Mar 08, 2006 8:29 am
Location: Luleå, Sweden
Contact:

Re: used to be

Post by Trekmeister » Wed Apr 11, 2007 4:08 am

nzimmers wrote: wrong, I wish I could find the guy that wrote the above cr*p and jolt him with 1 volt with 200amps and see what he feels (actually he wouldn't feel anything cause he would be dead from the instantanious cooking his body would suffer)

according to this genius from Hardocp, I shouldn't feel the 120volts from the power outlet in my kitchen right?
Ok the whole "its the current, not the voltage, that kills you" has always annoyed me. Sure, in a way it is true, if there is no current nothing will happen! But to get enough current floating through your body (which has a pretty high resistance) you need a voltage high enough.

Have you ever touched the two poles of a car battery at the same time? Did you die? Did you even feel it? A car battery can usually supply more than 100A of current but the voltage isn't high enough to form a current high enough through your body.

Lets use the famous law by that Ohm dude - I = U / R
Lets my body has somewhere around 100kOhm resistance (taken out of the air, but not that an unlikely number) and I touch the poles of a car battery I get the current of 12/100 000 = 0.12mA through me. If you were soaked in water and thereby lowered your skin resistance maybe you would have felt something... Or punctured your skin like in that guy who got a darwin award. (compare to a 9V battery against your tounge, which definetley kan be felt because of the very thin skin)


Anyhow, regarding the original posters question it never hurts to be careful. I myself don't have an anti-static bracelet and to my knowledge I have not ruined any hardware... yet! touch wood!

Myself I always touch the computer case in some bare metal place to make sure I am at the same potential as the case ground. Touching a grounded radiator or similar before working in a non grounded or non plugged in computer could be bad, just so you know.

Your ring will not make any real difference either. True, static tends to prefer dischaging from a small pointy surface if possible, but you should really try to avoid having such large buildups to make that a problem. Also as long as you don't constantly brush that hair of yours while working inside your computer it should not be any problem. :)

edited for stoopid error

jaganath
Posts: 5085
Joined: Tue Sep 20, 2005 6:55 am
Location: UK

Post by jaganath » Wed Apr 11, 2007 4:33 am

Lets my body has somewhere around 100kOhm resistance (taken out of the air, but not that an unlikely number
Good ballpark figure;
link
the skin resistance, which ranges from about 1000 ohms for wet skin to about 500,000 ohms for dry skin. The internal resistance of the body is small, being between 100 and 500 ohms.
note its the skin, not the body, that has the big resistance.

Trekmeister
Posts: 83
Joined: Wed Mar 08, 2006 8:29 am
Location: Luleå, Sweden
Contact:

Post by Trekmeister » Wed Apr 11, 2007 4:53 am

Poor choice of words from me I have to admit that, of course I ment body and skin. As such is was not that bad of an estimate (for a dry skin/body) and in examples such as this as long as you are in the correct 10-multiplier (for which I have of course forgotten the correct english word) it is a quite ok estimate. I also mentioned that soaked in water the resistance would be lower.
jaganath wrote:
Lets my body has somewhere around 100kOhm resistance (taken out of the air, but not that an unlikely number
Good ballpark figure;
link
the skin resistance, which ranges from about 1000 ohms for wet skin to about 500,000 ohms for dry skin. The internal resistance of the body is small, being between 100 and 500 ohms.
note its the skin, not the body, that has the big resistance.

minibeardeath
Posts: 31
Joined: Fri Apr 06, 2007 9:25 pm
Location: walnut creek, CA
Contact:

thank you all

Post by minibeardeath » Wed Apr 11, 2007 6:52 pm

for the answers. but i now have a new (but related) question.
i dont have grounded plugs is my room (but i have a surge protector), and i was wondering if my computer case can build up a static charge cause it only has the plastic base touching the floor, and it seemes that it should build up a pretty big charge(via induction) considering how much power is flowing through all the various parts. is this true?

CallMeJoe
Posts: 207
Joined: Wed Aug 27, 2003 11:01 am
Location: Secession State

Post by CallMeJoe » Wed Apr 11, 2007 7:16 pm

nzimmers:
You're right about how much wrong sh*t there is on the internet. Your statements are a perfect example. I've worked in electronics for over 30 years, and can tell you I have absolutely no doubt about the dangers of ESD. I've seen photomicrographs of static discharge damage from a calibrated discharge of 150 volts. The circuit (1980 vintage, much less susceptible to damage than current finer scale circuits) wasn't destroyed outright, but it did have a carbon arc path set in the substrate between semiconductors. This type of random path leads to intermittent failures due to random current paths in the IC. Static discharge, even when it has no immediate apparent effect can drastically shorten the life expectancy of the circuit.

As to your statement about hitting him with "one volt at 200 amps", you obviously need to go back to basic electronics class. One volt will develop almost no current in a human body, regardless of how much potential current the current source has.

Finally, aircraft instrument circuits are never latest technology. A typical current production aircraft GPS Nav is run by an AMD 80186 processor because it is old proven technology, and it's all the processing power the unit needs. This older generation of processors is far less prone to ESD damage than your new 60nm CPU.

nzimmers
Posts: 271
Joined: Mon Dec 04, 2006 6:13 pm

Re: used to be

Post by nzimmers » Thu Apr 12, 2007 4:00 am

nick705 wrote: Good luck trying to instantaneously cook a human body with 200 watts... :P
please re-read...I said 200 AMPs...not volts.....

Sylph-DS
Posts: 223
Joined: Wed Apr 04, 2007 2:56 am
Location: The Netherlands

Re: used to be

Post by Sylph-DS » Thu Apr 12, 2007 4:24 am

nzimmers wrote:
nick705 wrote: Good luck trying to instantaneously cook a human body with 200 watts... :P
please re-read...I said 200 AMPs...not volts.....
Seriously, the irony in that cracked me up.

nick705
Posts: 1162
Joined: Tue Mar 23, 2004 3:26 pm
Location: UK

Re: used to be

Post by nick705 » Thu Apr 12, 2007 4:25 am

nzimmers wrote:
nick705 wrote: Good luck trying to instantaneously cook a human body with 200 watts... :P
please re-read...I said 200 AMPs...not volts.....
Re-read it yourself. You said 200A at 1V, which if you hadn't fallen asleep during primary school physics, you'd know equates to a power output of 200W. It's meaningless in this context anyway, as the posts above have pointed out and I won't bother repeating.

nzimmers
Posts: 271
Joined: Mon Dec 04, 2006 6:13 pm

Re: used to be

Post by nzimmers » Thu Apr 12, 2007 6:16 am

nick705 wrote:
nzimmers wrote:
nick705 wrote: Good luck trying to instantaneously cook a human body with 200 watts... :P
please re-read...I said 200 AMPs...not volts.....
Re-read it yourself. You said 200A at 1V, which if you hadn't fallen asleep during primary school physics, you'd know equates to a power output of 200W. It's meaningless in this context anyway, as the posts above have pointed out and I won't bother repeating.
LOL shame on me - you'll have to excuse my eyesight, did that post when I was well and truly over tired and brain not working.

I have an idea here that may actually do some good in getting to the bottom of this - let's just send this one into that show "mythbusters" and then we can sit back and enjoy a beer while one of there team rubs a cat against their face while walking on carpet with socks and repeatedly discharging onto a motherboard eh?

Is is possible that ESD can cause damage to components? sure - Lightning is ESD - but from a human, from a human finger, and what's the threshold here? how often does this actually damage a component? does anyone have any real numbers? does anyone have anything more than "I saw a picture, etc"?

Is it possible? - sure

likely? if so, how likely? are we talking 1 in ten , 1 in 100, 1 in 1000 esds from a finger result in damage? and which components are the most susceptable?

so.....that's my susgestion.....send it in to myth busters and see what conclusions they draw.

spookmineer
Patron of SPCR
Posts: 749
Joined: Sat Nov 11, 2006 6:02 pm

Post by spookmineer » Thu Apr 12, 2007 3:22 pm

Only if they are going to use your motherbaord :wink:

jhhoffma
Posts: 2131
Joined: Mon Apr 25, 2005 10:00 am
Location: Grand Rapids, MI

Post by jhhoffma » Fri Apr 13, 2007 6:25 am

ESD dangers are real. There's a reason most electrical components are handled in static-free areas.

As a person who deals with static issues on a daily basis (I work for a fabric company that uses large roller presses, known as calenders), you don't want to know how much static can be produced by things going round and round (or back and forth). I've watch guys get burned by a discharge after running only 50yds of fabric (not much by our standards) because he forgot to lay down the copper tinsel over the windup. He reached over to let some pressure off the brake, and I watched the arc from the roller to his hand about 4ft!!

Every step you take ungrounded builds potential and increases the risk of ESD damage. More often than not, it's dissipated before you touch a dangerous component, but it only takes once. At the very least, ALWAYS touch the case itself before monkeying with anything inside, or if working outside the case, touch the surface you are working on first.

Post Reply