> Could you explain exactly what ground planes are and how they work.
>
Ground planes are large areas of copper on a PCB (typ) that are a
low impedence path to a reference such as zerovolts (0V).
As the conductors we use are not superconductors.. i.e. they have
resistance, current flowing through them will create a voltage across
them. In some applications it is critical that the reference for one
component is the same or very close to the reference voltage of
another.
Ground planes can also have a shielding effect when it acts as a
short circuit to radiated E.M. energy and are sometimes one side or
one layer of a PCB.

Clear as mud?

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Lance Allen
Technical Officer
Uni of Auckland
Psych Dept
New Zealand
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