FreeLists / si-list / [SI-LIST] Re: impedance and Characteristic impedanece

["Kotson, Michael" <mkotson@xxxxxxxxxxx>]

Hi Arpad,
   Here's how I arrived at the answer, right or wrong...
Looking into the circuit (Z11), you basically see a 1 ohm resistor in =
parallel with a voltage controlled current source.  The impedance of the =
current source is equal to the voltage across the current source divided =
by the current through the current source.  If we let the voltage across =
the source equal Vo, then the current through the current source equals =
Io. However, the current through the source is related to Vo, in fact it =
is equal to -Vo.  So, the impedance of the source, Zs=3DVo/Io.  Io =
equals -Vo.  So the impedance of the source Zs=3DVo/-Vo which comes out =
to -1.  If you combine -1 in parallel with R1=3D1 ohm, you come out with =
an infinite impedance.

Is this close?  What a great interview question...

Thanks,
Mike


-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx on behalf of Muranyi, Arpad
Sent: Mon 4/9/2007 5:46 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: impedance and Characteristic impedanece
=20
Zheng,

I hope you wouldn't mind, but I don't want to
give away the answer that quickly...  I want
to get people to think a little, see a few
more replies (if anyone cares), and if no one
gets it right in a day or so I will jump in
to the rescue.=3D20

Arpad
-----------------------------------------------

-----Original Message-----
From: Zhenggang Cheng [mailto:zcheng@xxxxxxxxxx]=3D20
Sent: Monday, April 09, 2007 4:34 PM
To: Muranyi, Arpad; si-list@xxxxxxxxxxxxx
Subject: RE: [SI-LIST] Re: impedance and Characteristic impedanece

Why is it infinte? Any formula ? Why it is not =
R=3D3DU/I=3D3DU/1*U=3D3D1?

And why this is related to impedance and characteristic impedance?

Sorry for asking so many whys. But I do want to know.

Thanks,

Zheng
------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

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


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

List archives are viewable at:    =20
                http://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
 =20



*****************************************************************
*************
CONFIDENTIAL NOTE: This e-mail and any attachments may be 
confidential and protected by legal privilege. If you are not 
the intended recipient, be aware that you are hereby notified 
that any unauthorized review, use, disclosure, dissemination, 
distribution, or copying of this communication, or any of its 
contents, is strictly prohibited. If you have received this 
email in error, please notify us immediately by replying to the 
sender and deleting this copy and the reply from your system. 
Thank you for your cooperation. 

EXPORT CONTROLLED DOCUMENT 
This document may contain information whose export is restricted 
by the Arms Export Control Act (Title 22, U.S.C., Sec 2751 Et 
Seq.) or the Export Administration Act of 1979, as amended, 
(Title 50, U.S.C., App. 2401, Et. Seq.) Violations to these 
export laws are subject to severe criminal penalties.  

All technical data forwarded by VT Miltope to its suppliers is 
EXPORT CONTROLLED. Supplier shall not disclose technical data in 
any form to a Foreign Person (including foreign person employees 
of Supplier), or export the technical data from the United 
States without U.S. Government authority and the written 
authorization of VT Miltope Contracts Department. 
*****************************************************************
*************
------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

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


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

List archives are viewable at:     
                http://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