[SI-LIST] Re: DC resistance measurement

  • From: <Aubrey_Sparkman@xxxxxxxx>
  • To: <taylor.jones@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
  • Date: Wed, 23 Aug 2006 15:13:34 -0500

To be "Kelvined" means to use one pair of leads to supply the current
and another pair of leads to sense the voltage.  Google "Kelvin four
point probe" and you will find several articles.  This looked pretty
good when I gave it a quick scan.

Two-Point and Four-Point Methods for Measuring Small Resistances  The
four-point resistance measurement method eliminates lead resistance or
... Special connecting clips called Kelvin clips are made to facilitate
this kind ...
www.sciencebuddies.org/mentoring/project_ideas/Elec_p025.shtml?from=3DHom=
e
-=20


Aubrey Sparkman=20
Enterprise Engineering Signal Integrity Team
Dell, Inc.=20
Aubrey_Sparkman@xxxxxxxx=20
(512) 723-3592

The Greatest Pleasure in Life is Doing what People say can't be done...

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Taylor Jones
Sent: Wednesday, August 23, 2006 2:42 PM
To: si-list
Subject: [SI-LIST] Re: DC resistance measurement

On 8/22/06, Andrew Ingraham <a.ingraham@xxxxxxxx> wrote:
>
> Accurate DC resistance measurements sometimes require a "kelvin" or=20
> 4-lead connection ... two leads to pass current through the device,=20
> and two
> *separate* leads for measuring the resulting voltage drop.  That way,=20
> I*R voltage drop across the connection points, leads, etc. is negated.


This brings up a term for which I was looking for more information, but
couldn't find anything. I have an AppNote that says:

The traces to and from the FET's source and the VDDEXT supply pin on the
Blackfin processor should, if possible, be Kelvined to their power
supply to avoid transient effects on other devices connected to the same
supply.

What exactly does it mean to be "Kelvined" to their power supply?

~ Taylor

Regards,
> Andy
>
> > Now, we are measure DC resistance of power plane in PCB. The=20
> > presision should be 0.1 mohm at least. However, because of the clamp

> > of the meter, the error is about 1m ohm. In another word, the=20
> > difference between two measurement for the same DUT is about 1 mohm.

> > Is there any advice about this topic? Anything will be help. In your

> > measurement, how to connect
> the
> > probe to the plane?
>
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