Jim Kelley wrote:
Cecil Moore wrote:
I(x,t) = Imax sin(kx) cos(wt)
For any point location 'x', it can be seen that the standing
wave current is not "flowing" in the ordinary sense of the word
but rather, is just oscillating in place at that fixed point.
According to the equation you provide above, for any point location 'x',
the phase of the current varies continuously with t. Presumably that is
what it means to just oscillate in place.
Of course, that's what it means. It doesn't move right or left.
I(x,t) = Imax sin(kx) cos(-wt) would be just as accurate a
description. One cannot even tell which way the standing-wave
phasor is rotating. This equates to putting the source
on either end of a lossless stub without anything changing.
Standing-wave current phase is unchanging up and down a lossless
stub. Standing-wave current phase changes hardly at all up and
down a stub with losses or a wire 1/2WL dipole. That current
cannot be used to obtain a valid delay through a wire or a coil.
--
73, Cecil
http://www.w5dxp.com