Re: gEDA-user: Question for DJ about his alarm clock

[John Doty <jpd@xxxxxxxxx>]

On Aug 15, 2008, at 6:16 PM, der Mouse wrote:

>> The power plane?  That board has two planes (power and ground).  Why
>> is one always the reference?
>
> In low-voltage electronics, there is no such thing as a voltage in
> isolation; voltage exists only in reference to somewhere else.
>
> In high-voltage electrostatics work, there is an absolute reference,
> that being "electrically neutral", as in "having equal amounts of
> positive and negative charges".

It's still relative. Take an electrically neutral object, place it in  
an electrostatic shield. Raise the shield potential to a billion  
volts above your reference point. The neutral object is also now at a  
potential of a billion volts above your reference point.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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