How to properly discharge static electricity?


P

PeterM

I work on computers every once in a while, and always wonder what the proper
way is to get rid of the static electricity. I always thought that I had to
be grounded to the little screw that holds the wall socket on. Also I
noticed one guy stick a banana plug into the neutral hole in a wall socket,
and then the other end of course was to a wrist band. One of my guys says
all I have to do is touch the computer case a couple of times and then the
static electricity is gone, and I can touch the memory stick, or whatever I
have to take out of the computer. It just doesn't make sense to me to just
touch the case. I use to have a little box that actually showed when the
static electricity was gone, where do I find that again......Could someone
please explain this to me. Thanks in advance..........Peter
 
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J

jeffrey

Hi,

for most people who work on electronics, we usually put on a static strap.
The strap goes around the wrist of the hand that will have the most contact
with electronic componets. The wire to the strap is then connected to a
ground of some sort, sometimes you can use the case that the componets are
housed in, as long as that case is grounded.

As for the PC componets, as long as you do not touch the IC chips, connector
pins, you will be safe, just hold the cards by the sides, the circuit card
edges. As for the CPU, it is recommended to have your hand grounded, before
inserting it. I haven't done that, but haven't had any problems, since I
limit how much of the CPU I touch while inserting it.

Jeff
 
W

w_tom

Appreciate the circuit that causes static electric
discharge. Charges have built up in a capacitor called your
shoes. Touch the motherboard. Charge travels up you hand,
through computer, down table to floor and back to shoes. Or
out of computer via safety ground wire, into wall, then into
floor and the soles of your shoes. To protect electronics,
then connect an anti static wrist strap to discharge your
shoes without going through electronics.

The only ground involved is static electricity is the one
beneath your shoe.
 
P

PeterM

Thanks for that explanation, I will also pass this on to my grandkids. They
never worried about this at all. I keep telling them to be careful about
this subject, but I guess I kept buying new stuff for them, when they
screwed something up. I just can't do the tuff love stuff. Many thanks again
for the kind and generous advise.........Peter
 
J

Jim Macklin

CyberGuys www.cyberguys.com has a neat catalog. They have
a short green cable that looks like a computer power cord,
except it only has one wire, the ground wire. You unplug
the power cord at the back of the computer, insert the green
ground and plug it all back together. The computer is then
grounded to the house electrical system giving a path for
extra electrons to flow to ground. A well designed computer
case will act as a capacitor and can absorb a rather large
amount of free electrons. But there still could be a high
voltage stored on the computer.
Depending on the humidity, the kind of clothes you're
wearing, your shoes, socks and the floor and furniture, the
electrons may dissipate quickly or they may sit there as
static electricity. In dry conditions without a path to an
adequate ground the voltage can be in the thousands. Since
modern chips operate at or less than 3 volts (some are
around 1.5 volts now) it is easy to short out a chip if the
path to ground is through a chip circuit.

You can find all kinds of ESD grounding straps in the
CyberGuys catalog or at your local electronics hobby store.

To learn more, Google for ESD, electrostatic control, static
electricity + computers and you'll have a lot of info.
Electrostatic Discharge Association
The ESD Association is a professional voluntary association
focusing on the effects
and control of static electricity and electrostatic
discharge (ESD). ...
www.esda.org/ - 19k - Dec 15, 2004 - Cached - Similar pages

ESD Journal - The ESD & Electrostatics Magazine
.... Search Magazine. Suit In for all ESD Needs. ESD Journal
Test Methods. ESD Journal
Seal of Approval. Company Profile: Fowler Past Co. ... ESD
Association. Basics of ESD ...
www.esdjournal.com/ - 101k - Dec 15, 2004 - Cached - Similar
pages

Webopedia: Static Electricity and Computers ... Static
Electricity and Computers. ... Also, computers become
increasingly susceptible to static electricity damage as
more and more circuitry is built into them. ...
www.webopedia.com/DidYouKnow/
Computer_Science/2002/static.asp - 34k - Cached - Similar
pages


Controlling Static Electricity - Stop Getting Shocks -
Succeed in ... ... Static electricity can cause sparks and
other problems. ... Grounding is also used to prevent sparks
from damaging computers and houses and causing explosions.
....
www.school-for-champions.com/science/staticcont.htm -
21k - Cached - Similar pages


PCWorld.com - Avoid Static Damage to Your PC ... and getting
zapped by a charge of static electricity, what's technically
.... and for the sensitive electronics inside a PC, static
can be a computer-killer. ...
www.pcworld.com/howto/article/0,aid,82184,00.asp -
Similar pages



--
Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin
| Thanks for that explanation, I will also pass this on to
my grandkids. They
| never worried about this at all. I keep telling them to be
careful about
| this subject, but I guess I kept buying new stuff for
them, when they
| screwed something up. I just can't do the tuff love stuff.
Many thanks again
| for the kind and generous advise.........Peter
|
| | > Appreciate the circuit that causes static electric
| > discharge. Charges have built up in a capacitor called
your
| > shoes. Touch the motherboard. Charge travels up you
hand,
| > through computer, down table to floor and back to shoes.
Or
| > out of computer via safety ground wire, into wall, then
into
| > floor and the soles of your shoes. To protect
electronics,
| > then connect an anti static wrist strap to discharge
your
| > shoes without going through electronics.
| >
| > The only ground involved is static electricity is the
one
| > beneath your shoe.
| >
| > PeterM wrote:
| >> I work on computers every once in a while, and always
wonder what
| >> the proper way is to get rid of the static electricity.
I always
| >> thought that I had to be grounded to the little screw
that holds
| >> the wall socket on. Also I noticed one guy stick a
banana plug into
| >> the neutral hole in a wall socket, and then the other
end of course
| >> was to a wrist band. One of my guys says all I have to
do is touch
| >> the computer case a couple of times and then the static
electricity
| >> is gone, and I can touch the memory stick, or whatever
I have to
| >> take out of the computer. It just doesn't make sense to
me to just
| >> touch the case. I use to have a little box that
actually showed when
| >> the static electricity was gone, where do I find that
| >> again......Could someone please explain this to me.
Thanks in
| >> advance..........Peter
|
 
A

Al Dykes

Thanks for that explanation, I will also pass this on to my grandkids. They
never worried about this at all. I keep telling them to be careful about
this subject, but I guess I kept buying new stuff for them, when they
screwed something up. I just can't do the tuff love stuff. Many thanks again
for the kind and generous advise.........Peter

OT: Machines should be unplugged, since modern machines have live voltage
on the motherbord, even if the power switch is off.

99% of the time I just grab the chassis before I touch a a part. If
I'm handing an expensive part, or I'm working on a server that _has_
to be running in the morning I grap the static strap.

Static charges too small for you to sense can blow out a chip, or do
damage that will make it fail in the near future.
 
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J

jazz

PeterM said:
I work on computers every once in a while, and always wonder what the proper
way is to get rid of the static electricity. I always thought that I had to
be grounded to the little screw that holds the wall socket on. Also I
noticed one guy stick a banana plug into the neutral hole in a wall socket,
and then the other end of course was to a wrist band. One of my guys says
all I have to do is touch the computer case a couple of times and then the
static electricity is gone, and I can touch the memory stick, or whatever I
have to take out of the computer. It just doesn't make sense to me to just
touch the case. I use to have a little box that actually showed when the
static electricity was gone, where do I find that again......Could someone
please explain this to me. Thanks in advance..........Peter
The theory behind touching the sides or metal frame of the case is that it
would equalize the statice charge between you and the computer making it
unlikley to have a discharge by other means (voltage arc). However sound
this is or not can be debated but i have almost always used this method
except if i am working with a monitor or television set. I don't think it
would eliminate all possibilities of static discharge but it should
eliminate most. Combine this with some anti static carpet or pads at the
workbench or maybe even a gounded work area that the computer sits on and
you should be pretty safe. The older electronic used in computers were more
suspectable to static damage then the newer commponants are. i don't really
think it is as serious of an issue as it was at one time.
 
M

Mikey

Hi,
To: Al Dykes.
Machine unplugged: means NO static discharge path.
You're asking for "it".
The built-in voltage when present is totally irrelevant vs your body's static
charge and that is what discharges thru the ground terminal.
1st: Touch the grounded case with today's electronic (pc) parts.
Add a grounded wrist-strap for that "smiley" feeling.
 
G

Gary

Putting a wire or a plug arrangement in a power socket is a recipe for some
nasty Volts coming your way. Things happen, earths become corroded, and
chewed by rats and mice, insulation breaks down, people wire outlets
incorrectly.......If you want a good earth drive a copper stake in the
ground & stay away from power sockets.

Touching the case is good, cause the charge dissipates over the metal, but
can build as soon as you move around again.
 
P

PeterM

Many thanks, you guys are so great. At least I have a better understanding
of this issue. I will wear a strap from now on, and figure out a way to
ground myself. I will check out that device at cyberguys, thanks
Jim...........Bless you all for this advise...... Grandpa in CA
 
J

Jim Macklin

You're welcome


--
Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin
| Many thanks, you guys are so great. At least I have a
better understanding
| of this issue. I will wear a strap from now on, and figure
out a way to
| ground myself. I will check out that device at cyberguys,
thanks
| Jim...........Bless you all for this advise...... Grandpa
in CA
|
| | > Putting a wire or a plug arrangement in a power socket
is a recipe for
| > some nasty Volts coming your way. Things happen, earths
become corroded,
| > and chewed by rats and mice, insulation breaks down,
people wire outlets
| > incorrectly.......If you want a good earth drive a
copper stake in the
| > ground & stay away from power sockets.
| >
| > Touching the case is good, cause the charge dissipates
over the metal, but
| > can build as soon as you move around again.
| >
| >
| > | >>I work on computers every once in a while, and always
wonder what the
| >>proper way is to get rid of the static electricity. I
always thought that
| >>I had to be grounded to the little screw that holds the
wall socket on.
| >>Also I noticed one guy stick a banana plug into the
neutral hole in a wall
| >>socket, and then the other end of course was to a wrist
band. One of my
| >>guys says all I have to do is touch the computer case a
couple of times
| >>and then the static electricity is gone, and I can touch
the memory stick,
| >>or whatever I have to take out of the computer. It just
doesn't make sense
| >>to me to just touch the case. I use to have a little box
that actually
| >>showed when the static electricity was gone, where do I
find that
| >>again......Could someone please explain this to me.
Thanks in
| >>advance..........Peter
| >
| >
|
 
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J

Jupiter Jones [MVP]

Peter;
The important thing is to have an equal potential between you and whatever
components you are working with.
The wrist ground between you and the case maintains that.
You have a problem when there is a difference between you and what you are
working with.
 
W

w_tom

The safety grounding wire from cyberguys does not solve your
static electric problem. IOW a charge generated from shoes
would still travel up the arm, through a first touched IC,
then continue out motherboard, through that safety ground
wire, to eventually complete the electrical circuit to bottom
of your shoes.

Damage is caused by electricity. Any device that has both
an incoming and outgoing path will conduct the electricity -
destructively. Static electric protection is not about
equalizing charges. It is about dissipating the charged
capacitor - your shoes. Trying to only equalize charges is a
recipe for damage. Any discharge path that conducts through
electronics will be destructive. That safety ground wire does
not solve static electric problems. Earth ground does not
address the 'grounding' of static electricity.

Lets look at how our professional workstations are
constructed. First we put a pink poly plastic sheet on the
concrete floor. To static electricity, the pink poly is a
perfect conductor. Then we connect that pink poly sheet to
the work desk. Anytime the worker touches the desktop, then
his shoes are completely discharged. Furthermore we put a
pink poly sheet on top of the desktop and connect that to the
floor mat. Then workers are connected to the desktop pink poly
sheet via an antistatic wrist strap. Now a worker need not
even touch the desktop to be discharged.

Furthermore, anti-static wrist strap must include about 1
megohm resistor. That resistor is essential to human safety.
This is an anti-static workstation. We do other things such
as connect all desktops to the common safety ground. We
install a humidifier. We eliminate all nylon rugs. We never
waste money on those anti-static sprays. In some locations,
we even worse white lab coats that contained conductive
threads and worried about floor wax. Some linoleum tile floor
waxes can create static electricity.

Furthermore, a computer sitting on a desktop is not
electrically isolated. Wood and other desktop materials
become conductors of static electricity. Trying to protect
the computer by electrically isolating it is neither feasible
nor practical.

One additional point. Static electricity is also a tool to
determine a properly assembled computer. With a computer on a
glass table top (because the desktop must be that little
conductive), static electric discharge to the computer on
every corner when computer is operating. Static electricity
would travel from human arm, across computer to power cord to
get back to bottom of shoes. And that computer software must
never be affected even by a discharge so strong as to create a
hurt. Only then is the computer properly assembled. Static
electricity must pass across the computer chassis and yet
never find a conductive path across motherboard.

Static electricity is a hazard during computer assembly.
Static electricity is also a power tool to confirm a complete
and proper assembly. That cyberguys ground wire provides no
static electric protection AND it could even complete the
static electric discharge circuit through motherboard ICs.
Static electricity damages when it has a complete electrical
circuit - a path both into and out of IC. You must discharge
the capacitor - your shoes - before touching anything
electronic. That is what the anti-static wrist strap does.
That is what touching the computer case (which conducts
through desk to your shoes) does. Discharge those charges on
shoes.
 
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P

PeterM

Wow, I appreciate this article a lot. My grandson will also appreciate it.
It does scare me a little, because now that I understand this a little
better, I will be forever conscious about the grounding and the ESD. What a
smart person you are Sir................Peter
 

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