[sdiy] Ground planes

[Harry Bissell]

"thermals" is short for "Thermal Relief Pads"... its a standard
term. They serve to prevent so much heat from being sucked into the
ground plane that soldering does not occur.

interesting side note... I just worked on a board that had "thermals"
on a ground pin of a connector. There were four traces across the
"moat". Too bad the designer tied that pin to three separate layers...
total of 12 connections. Needless to say, it could not be desoldered
without destruction.

The right move there would be to run a single trace (or two thin ones)
to a separate via nearby. Then the part could be desoldered and
the planes would still be connected.

gotcha!

H^) harry



----- Original Message -----
From: David Ingebretsen <dingebre at 3dphysics.net>
To: 'cheater cheater' <cheater00 at gmail.com>
Cc: 'synth-diy' <synth-diy at dropmix.xs4all.nl>
Sent: Tue, 30 Mar 2010 11:02:13 -0400 (EDT)
Subject: Re: [sdiy] Ground planes

It may be an Eagle specific term. Instead of just making a hole that is in
the groud plane, Eagle (and other PCB software) makes an isolated pad
connected to the ground plane with smaller traces. It's supposed to help
mitigate a heat sink effect when soldering components which connect to
ground.

David

~~ -----Original Message-----
~~ From: cheater cheater [mailto:cheater00 at gmail.com]
~~ Sent: Tuesday, March 30, 2010 5:14 AM
~~ To: David Ingebretsen
~~ Cc: synth-diy
~~ Subject: Re: [sdiy] Ground planes
~~ 
~~ Hi David,
~~ 
~~ > with "thermals", it's a
~~ > pain to solder pads connected to a ground plane.
~~ 
~~ what do you mean?
~~ 
~~ Thanks
~~ D.
~~ 
~~ On Tue, Mar 30, 2010 at 12:44, David Ingebretsen <dingebre at 3dphysics.net>
~~ wrote:
~~ > Is there any value to adding a ground plane fill to a PCB for the
~~ typical
~~ > types of circuits for audio module? How about one on both sides of a
two
~~ > sided PCB? Is there any difference in putting it on the top versus
~~ bottom?
~~ >
~~ > I'm getting ready to send a board off to be made. It's easy to add it,
~~ but
~~ > I'm not sure the theory behind it other than even with "thermals", it's
~~ a
~~ > pain to solder pads connected to a ground plane.
~~ >
~~ > I've noticed some PCB's I've purchased have them, but many don't and I
~~ > haven't heard any artifacts either way.
~~ >
~~ > Thanks,
~~ >
~~ > David
~~ >
~~ > David M. Ingebretsen M.S., M.E.
~~ > Collision Forensics & Engineering, Inc.
~~ > 2469 East Fort Union Blvd. STE 114
~~ > Salt Lake City, UT 84121
~~ > www.CFandE.com
~~ >
~~ > 801 733-5458 Office
~~ > 801 842-5451 Cell
~~ >
~~ > dingebre at CFandE.com
~~ > dingebre at 3dphysics.net
~~ >
~~ >
~~ >
~~ > _______________________________________________
~~ > Synth-diy mailing list
~~ > Synth-diy at dropmix.xs4all.nl
~~ > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
~~ >

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-- 
Harry Bissell & Nora Abdullah 4eva