Hi Victor:
                The wiring in the inductor or transformer is insulated,  but
the inductive voltage from the wiring transfers to the ferrite core as
magnetic flux voltage, and it is passed to the annular ring by contact and
may be strong enough to interfere with adjacent circuitry. As a rule, any
conductive material should be insulated if its proximity to another
conductor is less than the minimum spacing.
        Regards,
        Ramon

> -----Original Message-----
> From: Victor G. Hernandez [SMTP:[log in to unmask]]
> Sent: Friday, March 12, 2004 10:48 AM
> To:   [log in to unmask]
> Subject:      [TN] Ferrite Core Placement Inquiry
>
> Fellow TechNetters,
>
>    Is there any EXPOSURE with mounting a ferrite core from either an
> Inductor and/or
> Xfornmer directly on the surface of the PCB where the ferrite core
> material is in
> direct contact with the annular rings which are HASL.   My concern is
> that the ferrite
> core material is conductive.   Therefore, a potential difference could
> occur from
> contact with PTH annular rings.   I did not see subject matter covered
> in IPC Standards.
>
> Victor,
>
> ---------------------------------------------------
> 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
847-509-9700 ext.5315
> -----------------------------------------------------

---------------------------------------------------
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 847-509-9700 ext.5315
-----------------------------------------------------