Mike,
The figure in question is for temperature rise, given an amount of current
for a given cross-sectional area of copper, how hot will it get (see note 1
of Figure 3-4).  For 1 oz or 1/2 copper,  0.012 inches for 300mA should be
okay,  For a handy temperature rise calculator, go to
http://www.ultracad.com/calc.htm
and download PCBTemp.exe.  Microsoft VBRUN300.DLL is required to use it.
Roger M. Stoops, C.I.D., PCB Designer


Spectra Precision Inc./Trimble Navigation Ltd.
5475 Kellenburger Rd.
Dayton, OH 45424-1099 USA
Ph: 937.233.8921 or 937.233.4574 ext 288
Fax: 937.233.7511



                    Mike Cubon
                    <mcubon@ITWCHRONO        To:     [log in to unmask]
                    MATIC.COM>               cc:
                    Sent by: TechNet         Subject:     [TN] Tech question.
                    <[log in to unmask]>


                    10/28/00 02:24 PM
                    Please respond to
                    "TechNet E-Mail
                    Forum."; Please
                    respond to Mike
                    Cubon





My name is Mike Cubon and I work for ITW Chronomatic. We manufacture
Polymer
Thick Film circuits and I have a technical question about figure 3-4 in
IPC-D-275. There are three graphs that show current rating for different
conductor traces at different temperatures. Are there any charts or perhaps
a formula for calculating current capacity below the temperatures shown.
The
application is automotive and will be tested to -40C. The max. current will
be 300mA and trace width will be .012 inches.

Any help is greatly appr.

Mike

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

Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
---------------------------------------------------------------------------------

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------