TECHNET Archives

December 2004

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Blair K. Hogg" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Blair K. Hogg
Date:
Wed, 15 Dec 2004 05:33:39 -0800
Content-Type:
text/plain
Parts/Attachments:
text/plain (67 lines)
Phil,
 
I'm curious, when you measured these did you use a 4-wire meter or some other method to eliminate the meter lead resistance?
 
Blair

>>> [log in to unmask] 12/14/04 07:26PM >>>
Just some further findings on this particular problem;

There are four through hole connector pads (A,B,C,D) in a row,  each pad
0.8 inches from the next pad.
There is a 6 thou, half ounce track (same internal layer) running in
parallel with the four pins, about 100 thou from the pads.
The four pins are connected to the pads with stubs. IE: the traces do
not go through the pads

The resistance measurements are as follows:
A to B =  1.2 ohms
B to C =  1.2 ohms
C to D =  1.2 ohms

A to C =  2.5 ohms
B to D =  2.5 ohms

A to D =  3.7 ohms

Which makes the trace stub and pad/via resistance approx 0.05 ohms
And the parallel trace resistance between any two adjacent pins approx
1.2 ohms

The other internal layer is the same, but the A to D resistance is 2.4
ohms

Some other PCBs show approx identical resistances
While others have different resistance but the same ratios
Some are OK

None of the external traces show this effect. Even those going through
vias from the top to the bottom of the PCB.

regards,

Phil.



*******************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.

This footnote also confirms that this email message has been swept
for the presence of computer viruses.

www.hubbell.com - Hubbell Incorporated

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2