[SI-LIST] Re: Displacement vs conduction current Q & A from Dr Archambeault

From: "Grasso, Charles" <Charles.Grasso@xxxxxxxxxxxx>
To: "'si-list@xxxxxxxxxxxxx'" <si-list@xxxxxxxxxxxxx>
Date: Tue, 12 Oct 2004 12:32:23 -0600

Question:
 
Hello Dr. Archambeault,
 
Mr. Grasso provided your email and suggested to contact you directly.
After going through your presentation slides, I have couple questions on
displacement currents vs conduction currents. 

1. Do they have comparable magnitudes?
2. Do they flow at comparable speeds?
 
I appreciate any ideas you could share with me. I will not divulge any info
without your permission.

Thanks,
Sitar
 
 
 Answer:
Sitar, 

I am not sure exactly what you are asking, but your first question about
comparable amplitudes........if you are talking about the effects where
signal current flows through a via (for example), and there is no nearby
'ground' via, then all the signal current must flow through the dielectric
as displacement current.  So, in this case, the amplitudes are the same.  If
there is a 'ground' via near enough to have an effect (within ~ 200 mils)
then the return current will split itself between the 'ground' via and the
displacement current.  the total will be the same as the original signal
current.  Th ebottom line is that current MUST return to its
source.....somehow....and using the path of least inductance. 

the speed of these currents is the same, since the dielectric (around the
conductor for the conduction current, or thru the dielectric for
displacement current) is the same in both cases. 

I hope this helps 

bruce 

----------------------------------------------------------------------------
--------------------------------------------------


Bruce Archambeault, Ph. D. 
Senior Technical Staff Member
EMC CoC
919-486-0120
t/l 526-0120

 
Best Regards
Charles Grasso
Senior Compliance Engineer
Echostar Communications Corp.
Tel:  303-706-5467
Fax: 303-799-6222
Cell: 303-204-2974
Email: charles.grasso@xxxxxxxxxxxx; <mailto:charles.grasso@xxxxxxxxxxxx; >

Email Alternate: chasgrasso@xxxxxxxx <mailto:chasgrasso@xxxxxxxx> 
 
 


------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List FAQ wiki page is located at:
                http://si-list.org/wiki/wiki.pl?Si-List_FAQ

List technical documents are available at:
                http://www.si-list.org

List archives are viewable at:     
                //www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

[SI-LIST] Re: Displacement vs conduction current Q & A from Dr Archambeault

Other related posts: