[SI-LIST] Re: characteristic impedance at DC

  • From: "Beal, Weston" <Weston_Beal@xxxxxxxxxx>
  • To: "haaeri@xxxxxxxxx" <haaeri@xxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
  • Date: Mon, 9 Apr 2012 22:49:59 +0000

Characteristic impedance applies to propagating EM waves, so it does not apply 
to DC. 

Or, if you look at the general equation that you cited, you can see that when 
jw = 0, the impedance approaches the line resistance. Somewhere in college I 
remember seeing a graph of the general impedance equation compared to actual 
measurement at low frequency. They are the same above some kHz, but diverge as 
frequency decreases.

Weston


-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On 
Behalf Of mohammad haaeri
Sent: Monday, April 09, 2012 3:31 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] characteristic impedance at DC

Hi,
What is the characteristic impedance of a transmission line at DC? If you are 
saying Z0=sqrt(Rdc/Gdc) at DC, since Gdc=0, and Rdc is not zero, therefore Z0 
is infinite. Is it correct?

How does behavior of L, R, G, and C (line parameters) change vs. frequency (at 
low and DC, and at very high frequency)?

Can Z0=sqrt(R+jwl/G+jwc) be used for all frequencies?

Thanks,
mohammad


------------------------------------------------------------------
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 forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

List archives are viewable at:     
                //www.freelists.org/archives/si-list
 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
  

------------------------------------------------------------------
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 forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

List archives are viewable at:     
                //www.freelists.org/archives/si-list
 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
  

Other related posts: