LISTSERV mailing list manager LISTSERV 16.5

Help for PCBUILD Archives

   

PCBUILD Archives

PCBUILD Archives


PCBUILD@LISTSERV.ICORS.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

PCBUILD Home

PCBUILD Home

PCBUILD  June 2009

PCBUILD June 2009

Subject:

Re: Fw: [PCBUILD] It is neither necessary nor desirable to ground the case to a wall socket - follow-up

From:

Robert Citkowitz <[log in to unmask]>

Reply-To:

Personal Computer Hardware discussion List <[log in to unmask]>

Date:

Sun, 21 Jun 2009 14:08:46 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (78 lines)

That was the problem, Dean! I was too busy holding up... Oh, well... :) But interesting info!

My concern stemmed from having "zapped" my VCR long ago when touching it - with spark - after walking on a carpet. It shut down, and needed an unplugging boot to restart.

Rob
 
----- Original Message ----- 
From: Dean Kukral 
To: [log in to unmask] 
Sent: Saturday, June 20, 2009 2:36 PM
Subject: [PCBUILD] Fw: [PCBUILD] It is neither necessary nor desirable to ground the case to a wall socket - follow-up


Well, it is impossible to say no, but "zapping" might be a bit strong.

This phenomenom is related to that of lightning striking a car.  I have heard that inside a car is one of the safest places to
be during a lightning storm, because you are surrounded by a metallic sphere.  But, if you touch the door handle while it strikes,
might you still be safe or can you get shocked?  That is the question, here.  The answer might depend on several variables, such as
where the lightning strikes, is the car grounded or insulated from ground, and other conductive situations.  You are asking if you
are safer in the car if it is grounded than if it is not grounded.  (For example, your tires are dry.)

Charge will tend to go to the outside of the case, and, from there, drain off at sharp edges.  It is not inconceivable that for an
instant some charge would dristribute itself into the the innards of the computer to those parts that are grounded, such as the 
substrate
of the integrated circuits, if grounded.  [The motherboard likely has a thin copper ground plane (or they used to) which would slow
things up.]  It is only speculation on whether it could do any damage, and, if so, how much.  I am not knowledgeable about static
damage, but my understanding has been that damage comes from zapping a chip, causing immediate burn damage, burning
out the aluminum and other microscopic connectors, and weakening others.

Whether grounding the case would lessen the potential for damage is also speculative.  IF damage is possible, then grounding the
case first might lessen the chances for damage, because the ground would give a low-resistance path to ground for the current
as opposed to the capacitive path into the logic.  Certainly, like the car, the inside configuration and overall construction
of the case would have some effect on the outcome.

Perhaps some research has been done in this area that someone knows about, not just speculation.  It might make a good senior
project for an EE student who has sensitive measuring equipment at his/her disposal.

This can all be prevented by placing a resistor in the wrist strap to prevent "zapping," but you would want the alligator clips
insulated, too, or the purpose of the resistor would be defeated.

I have heard that static damage is most likely to circuit boards when the board is out of the case, so stuff should be kept in the
plastic bags for that reason.  When the boards are plugged in to the case (motherboard, memory, video card, etc.), they are
relatively safe because they are grounded to the case.  Your pose an interesting question because of the immediate impulse of charge
as opposed to the slow introduction of charge.  For example, if you carry the case across the carpet, there is virtually no danger
to the components.  It is the components out of the case that are most vulnerable.  But, that assumes, of course, that  you are not
walking across the carpet and then immediately touching an ic!

Maybe if you wear a belt AND suspenders, you would ground yourself first to something else and then attach yourself to the computer.
:)

Dean Kukral


----- Original Message ----- 
From: Robert Citkowitz
Sent: Saturday, June 20, 2009 11:15


What-if question:

If you connect yourself to the uplugged computer via wrist strap, couldn't you be zapping the computer/chips with whatever static
charge you had built up (eg, the surprising, sparking amount you get during the dry winter after walking on a carpet) on the way to
the computer?

Rob


<snip> 

               The NOSPIN Group Promotions is now offering
                 our special coffee mugs and mouse pads
              with the PCBUILD logo...  at a great price!!!
             http://freepctech.com/goodies/promotions.shtml

        The NOSPIN Group has added a new feature on our website,
           web based bulletinboard for questions and answers:
              Visit our sister website at http://nospin.com

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

June 2018, Week 1
September 2017, Week 3
June 2017, Week 4
June 2017, Week 3
June 2017, Week 2
May 2017, Week 2
May 2017, Week 1
April 2017, Week 1
October 2016, Week 4
October 2016, Week 1
September 2016, Week 5
September 2016, Week 4
August 2016, Week 4
August 2016, Week 1
July 2016, Week 5
July 2016, Week 4
July 2016, Week 3
June 2016, Week 4
June 2016, Week 3
May 2016, Week 4
May 2016, Week 3
May 2016, Week 2
May 2016, Week 1
March 2016, Week 5
March 2016, Week 3
March 2016, Week 2
March 2016, Week 1
February 2016, Week 3
January 2016, Week 4
January 2016, Week 3
January 2016, Week 2
January 2016, Week 1
December 2015, Week 4
December 2015, Week 3
December 2015, Week 2
December 2015, Week 1
November 2015, Week 3
October 2015, Week 4
October 2015, Week 3
October 2015, Week 1
September 2015, Week 5
September 2015, Week 2
August 2015, Week 4
August 2015, Week 3
July 2015, Week 4
July 2015, Week 3
July 2015, Week 1
April 2015, Week 3
April 2015, Week 1
March 2015, Week 1
February 2015, Week 1
January 2015, Week 5
January 2015, Week 3
January 2015, Week 2
January 2015, Week 1
December 2014, Week 5
December 2014, Week 4
December 2014, Week 3
December 2014, Week 2
December 2014, Week 1
November 2014, Week 4
November 2014, Week 3
November 2014, Week 2
November 2014, Week 1
October 2014, Week 4
October 2014, Week 3
August 2014, Week 4
August 2014, Week 3
August 2014, Week 2
August 2014, Week 1
July 2014, Week 5
July 2014, Week 4
July 2014, Week 2
July 2014, Week 1
June 2014, Week 3
June 2014, Week 2
May 2014, Week 4
May 2014, Week 3
May 2014, Week 2
May 2014, Week 1
April 2014, Week 5
April 2014, Week 1
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
January 2002
December 2001
November 2001
October 2001
September 2001
August 2001
July 2001
June 2001
May 2001
April 2001
March 2001
February 2001
January 2001
December 2000
November 2000
October 2000
September 2000
August 2000
July 2000
June 2000
May 2000
April 2000
March 2000
February 2000
January 2000
December 1999
November 1999
October 1999
September 1999
August 1999
July 1999
June 1999
May 1999
April 1999
March 1999
February 1999
January 1999
December 1998
November 1998
October 1998
September 1998
August 1998
July 1998
June 1998
May 1998
April 1998
March 1998
February 1998

ATOM RSS1 RSS2



LISTSERV.ICORS.ORG

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager