Mailinglist Archive: opensuse (3666 mails)

[Randall R Schulz <rschulz@xxxxxxxxx>]

Hi, Carlos,

On Monday 21 March 2005 12:40, Carlos E. R. wrote:
> The Monday 2005-03-21 at 06:56 -0800, Randall R Schulz wrote:
> > GFCIs essentially _infer_ that current is traveling to ground
> > because there's unequal current flow through the two power wires.
> > (Kirchoff's laws to the rescue). The _assumption_ (a conservative
> > one) is that the current is flowing through a human. Humans are
> > notoriously ill-suited for use as electrical conductors.
>
> English is a nice language for some kind of humor :-p
>
> > Hmmm... I wonder, how do GFCIs deal with reactive loads? Do they
> > time average the current measurement over several cycles?
>
> ...
>
> Thus, they are current sensitive devices. They don't sense voltage,
> only instantaneous current (really average), and thus know nothing
> about reactive load (ie, they can not measure the I·A phase
> difference), they are all the same to it. They would trigger.

Right, right. That's why I switched from EE to CS.

Del dot B = 0 my ass. Electrostatics was tolerable, but electrodynamics 
was just not worth it. And what's the deal with exponentials in the 
current / voltage relationship in semiconductor junctions? That's nuts!


>        Carlos Robinson


Randall Schulz