On Dec 14, 9:40 am, Cecil Moore wrote:
AI4QJwrote:
If it were possible for the source to provide DC
current at c, then the DC current moves at c.

The step function from zero to DC contains a lot
of frequencies. I suspect photons are involved
at the leading edge of the DC pulse.
--
73, Cecil http://www.w5dxp.com

Right, the step function has a number of sinusoids associated with it
which are affected by Zo and that was already addressed. Richard's
challenge was to address the velocity of DC at steady state, after the
transients from the step died down.