RE: [SI-LIST] : Simple question about propagation speed vs. diele ctric

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From: Offer Kaye (
Date: Sun Feb 18 2001 - 02:39:10 PST

EM waves propogate by the movement of photons, electrical signals
propogate by the movement of charge carriers- only electrons in our case,
but in semiconductors also sometimes holes. EM waves usually move at a
speed very close to their speed in vacuum (3*10^8 m/s), electrical signals
usually around "only" 2/3 of that value.
So no, they are definitly not the same.

Is this the distinction you meant?

Offer Kaye
Web Site:

On Sun, 18 Feb 2001, Chris Padilla wrote:

> I am not sure I understand the difference between EM wave propogation and
> electrical signals propagation velocity. Isn't EM waves and electrical
> signals the exact same thing?
> Of course whether or not it is a wave largely depends on the
> frequency/wavelength one considers or "cares about".
> I guess I don't follow your distinction. It is interesting so I wonder if
> you could clarify.
> Thanks----->Chris
> >Last but not least, remember the basic difference between EM wave
> >propagation and electrical signals propagation speed: EM waves depend on
> >the Er of the medium through which they are travelling, electrical signals
> >depend on the Er of the surrounding dielectric.
> >
> >Hope this helps... :)
> >
> >Offer Kaye
> >

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