[sdiy] Ground planes

[Magnus Danielson]

David Ingebretsen wrote:
> 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.
It is a widespread term, it just isn't used in the audio-realm since the 
need for ground-planes is almost none.
The thermal as a function may need a bit of explanation. If you have a 
ground-plane and makes a hole in it, soldering (and de-soldering) 
becomes troublesome as the heat disappates into the plane very 
efficiently. The solution is to make a clearence around the hole, make a 
normal hole and pad, and then draw either two or four wires to the 
surrounding ground-plane. That is a compromise to solve both problems.

If a hole into a large plane causes soldering or de-soldering problems, 
pre-heating with a hot-air gun helps a lot.

One reason for ground-planes on both sides is to use up less of the 
solution in the etch-tank.

Certain design-features such as oscillator comparators and such may have 
a bit sharp edges, so some care might be taken, but full-featured ground 
plane may not be needed.

Cheers,
Magnus