Re: Electron Flow
Ross: I'm with you. The earth represents the reference plane so the charge actually moves from the earth to the cloud to neutralize it. Ralph Cameron - Original Message - From: Hunt, Richard rh...@canoga.com To: 'Lichtenstein, Ross' ross.lichtenst...@owenscorning.com; 'Barry Ma' barry...@altavista.com; emc-p...@majordomo.ieee.org Sent: Thursday, October 05, 2000 12:23 PM Subject: RE: Electron Flow Here we go...this ought to be good. Richard Hunt Engineering Services Manager Direct: (818) 678-3860 Canoga Perkins Corp. Main:(818) 718-6300 20600 Prairie Street FAX: (818) 678-3760 Chatsworth CA 91311-6008 e-mail: rh...@canoga.com rh...@canoga.com -Original Message- From: Lichtenstein, Ross [mailto:ross.lichtenst...@owenscorning.com] Sent: Thursday, October 05, 2000 7:54 AM To: 'Barry Ma'; emc-p...@majordomo.ieee.org Subject: RE: Electron Flow Barry, I could be wrong, and if so I would stand corrected, but from my basic electronics training, I recall that electron flow is from negative to positive. I also recall being taught that lightning actually travels from earth (neg. charge) upward to the positive charge of the clouds. Then there is also the case of lightning between clouds of opposite charge, and again the electron flow direction is from neg. to pos. Ross -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Wednesday, October 04, 2000 5:58 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD Opportunities Please allow me to ask a relevant question only for curiosity. We have no idea of what charge (positive or negative) would go to the DUT in ordinary ESD. That's why we have to test two polarities in ESD immunity test. Lightning is a kind of ESD happened between a charged cloud and objects on earth surface. Some figures imply that an electron current flows from the charged cloud to the earth. Is it possible to have an opposite direction - electron flows from earth to cloud? Thanks. Barry Ma ___ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Electron Flow
I feel compelled to interject, having some experience in the area of lightning.
It's true that the majority of lightning return strokes are negative. However,
positive return strokes, usually occurring toward the end of a storm, do occur.
They also tend to have a larger magnitude, on average, than the more common
negative return strokes.
DB
--
From: pwmc...@ra.rockwell.com[SMTP:pwmc...@ra.rockwell.com]
Reply To: pwmc...@ra.rockwell.com
Sent: Thursday, October 05, 2000 9:46 AM
To: Lichtenstein, Ross
Cc: 'Barry Ma'; emc-p...@majordomo.ieee.org
Subject: RE: Electron Flow
Barry,
I believe Ross is right for the last and larger half (LARGER half??
{poetic license}) of a lightning strike. As I understand the current
lightning model the initial strike is a positive Leader coming from the
cloud to the ground. The Leader is a thin column of air that has been
ionized by the excessive potential between the cloud and ground. The
electrons move back towards the cloud, the positive air (nitrogen, oxygen,
water vapor, etc.) ions move towards the ground breaking down the air and
creating more ions as they go. The path is dependant on the instantaneous
breakdown potential of the closest air molecules to the leader causing the
characteristic jagged nature as it comes down. Once the leader reaches the
earth (tree, building, dirt...) The excess electrons rush back to the cloud
along the ionzed leader.
The lightening is a positive stroke downward followed by a large
Negative stroke upwards.
Paul McCoy
Lichtenstein, Ross ross.lichtenst...@owenscorning.com@ieee.org on
10/05/2000 09:54:21 AM
Please respond to Lichtenstein, Ross ross.lichtenst...@owenscorning.com
Sent by: owner-emc-p...@ieee.org
To: 'Barry Ma' barry...@altavista.com, emc-p...@majordomo.ieee.org
cc:
Subject: RE: Electron Flow
Barry,
I could be wrong, and if so I would stand corrected, but from my basic
electronics training,
I recall that electron flow is from negative to positive.
I also recall being taught that lightning actually travels from earth (neg.
charge) upward
to the positive charge of the clouds. Then there is also the case of
lightning between clouds
of opposite charge, and again the electron flow direction is from neg. to
pos.
Ross
-Original Message-
From: Barry Ma [mailto:barry...@altavista.com]
Sent: Wednesday, October 04, 2000 5:58 PM
To: emc-p...@majordomo.ieee.org
Subject: Re: ESD Opportunities
Please allow me to ask a relevant question only for curiosity.
We have no idea of what charge (positive or negative) would go to the DUT
in
ordinary ESD.
That's why we have to test two polarities in ESD immunity test.
Lightning is a kind of ESD happened between a charged cloud and objects on
earth surface. Some figures imply that an electron current flows from the
charged cloud to the earth. Is it possible to have an opposite direction -
electron flows from earth to cloud?
Thanks.
Barry Ma
___
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RE: Electron Flow
Barry,
I believe Ross is right for the last and larger half (LARGER half??
{poetic license}) of a lightning strike. As I understand the current
lightning model the initial strike is a positive Leader coming from the
cloud to the ground. The Leader is a thin column of air that has been
ionized by the excessive potential between the cloud and ground. The
electrons move back towards the cloud, the positive air (nitrogen, oxygen,
water vapor, etc.) ions move towards the ground breaking down the air and
creating more ions as they go. The path is dependant on the instantaneous
breakdown potential of the closest air molecules to the leader causing the
characteristic jagged nature as it comes down. Once the leader reaches the
earth (tree, building, dirt...) The excess electrons rush back to the cloud
along the ionzed leader.
The lightening is a positive stroke downward followed by a large
Negative stroke upwards.
Paul McCoy
Lichtenstein, Ross ross.lichtenst...@owenscorning.com@ieee.org on
10/05/2000 09:54:21 AM
Please respond to Lichtenstein, Ross ross.lichtenst...@owenscorning.com
Sent by: owner-emc-p...@ieee.org
To: 'Barry Ma' barry...@altavista.com, emc-p...@majordomo.ieee.org
cc:
Subject: RE: Electron Flow
Barry,
I could be wrong, and if so I would stand corrected, but from my basic
electronics training,
I recall that electron flow is from negative to positive.
I also recall being taught that lightning actually travels from earth (neg.
charge) upward
to the positive charge of the clouds. Then there is also the case of
lightning between clouds
of opposite charge, and again the electron flow direction is from neg. to
pos.
Ross
-Original Message-
From: Barry Ma [mailto:barry...@altavista.com]
Sent: Wednesday, October 04, 2000 5:58 PM
To: emc-p...@majordomo.ieee.org
Subject: Re: ESD Opportunities
Please allow me to ask a relevant question only for curiosity.
We have no idea of what charge (positive or negative) would go to the DUT
in
ordinary ESD.
That's why we have to test two polarities in ESD immunity test.
Lightning is a kind of ESD happened between a charged cloud and objects on
earth surface. Some figures imply that an electron current flows from the
charged cloud to the earth. Is it possible to have an opposite direction -
electron flows from earth to cloud?
Thanks.
Barry Ma
___
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RE: Electron Flow
Here we go...this ought to be good. Richard Hunt Engineering Services Manager Direct: (818) 678-3860 Canoga Perkins Corp. Main:(818) 718-6300 20600 Prairie Street FAX: (818) 678-3760 Chatsworth CA 91311-6008 e-mail: rh...@canoga.com rh...@canoga.com -Original Message- From: Lichtenstein, Ross [mailto:ross.lichtenst...@owenscorning.com] Sent: Thursday, October 05, 2000 7:54 AM To: 'Barry Ma'; emc-p...@majordomo.ieee.org Subject:RE: Electron Flow Barry, I could be wrong, and if so I would stand corrected, but from my basic electronics training, I recall that electron flow is from negative to positive. I also recall being taught that lightning actually travels from earth (neg. charge) upward to the positive charge of the clouds. Then there is also the case of lightning between clouds of opposite charge, and again the electron flow direction is from neg. to pos. Ross -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Wednesday, October 04, 2000 5:58 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD Opportunities Please allow me to ask a relevant question only for curiosity. We have no idea of what charge (positive or negative) would go to the DUT in ordinary ESD. That's why we have to test two polarities in ESD immunity test. Lightning is a kind of ESD happened between a charged cloud and objects on earth surface. Some figures imply that an electron current flows from the charged cloud to the earth. Is it possible to have an opposite direction - electron flows from earth to cloud? Thanks. Barry Ma ___ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Electron Flow
I came across an interesting reference. It appears that charge flow is both directions. See http://www.ee.ic.ac.uk/eee2proj/rtal97/physics.html especially Figure 5 at the bottom of the webpage. -- From: Lichtenstein, Ross[SMTP:ross.lichtenst...@owenscorning.com] Reply To: Lichtenstein, Ross Sent: Thursday, October 05, 2000 10:54 AM To: 'Barry Ma'; emc-p...@majordomo.ieee.org Subject: RE: Electron Flow Barry, I could be wrong, and if so I would stand corrected, but from my basic electronics training, I recall that electron flow is from negative to positive. I also recall being taught that lightning actually travels from earth (neg. charge) upward to the positive charge of the clouds. Then there is also the case of lightning between clouds of opposite charge, and again the electron flow direction is from neg. to pos. Ross -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Wednesday, October 04, 2000 5:58 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD Opportunities Please allow me to ask a relevant question only for curiosity. We have no idea of what charge (positive or negative) would go to the DUT in ordinary ESD. That's why we have to test two polarities in ESD immunity test. Lightning is a kind of ESD happened between a charged cloud and objects on earth surface. Some figures imply that an electron current flows from the charged cloud to the earth. Is it possible to have an opposite direction - electron flows from earth to cloud? Thanks. Barry Ma ___ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Electron Flow
Barry, I could be wrong, and if so I would stand corrected, but from my basic electronics training, I recall that electron flow is from negative to positive. I also recall being taught that lightning actually travels from earth (neg. charge) upward to the positive charge of the clouds. Then there is also the case of lightning between clouds of opposite charge, and again the electron flow direction is from neg. to pos. Ross -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Wednesday, October 04, 2000 5:58 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD Opportunities Please allow me to ask a relevant question only for curiosity. We have no idea of what charge (positive or negative) would go to the DUT in ordinary ESD. That's why we have to test two polarities in ESD immunity test. Lightning is a kind of ESD happened between a charged cloud and objects on earth surface. Some figures imply that an electron current flows from the charged cloud to the earth. Is it possible to have an opposite direction - electron flows from earth to cloud? Thanks. Barry Ma ___ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
