"xray4abc" <lemhenyil@yahoo.ca> wrote in message 
news:1163620888.625245.162710@b28g2000cwb.googlegroups.com...
| Consider an ideal metallic conductor,  connected,
| in a closed electrical circuit, to a non-ideal DC
| power source.
|  E=0 inside the conductor;

Whoa! Where did you get that idea?

Consider a vacuum tube such as a TV, connected,
in a closed electrical circuit, to a non-ideal DC
power source such as voltage tripler.

E=26,000 V at one end of the vacuum and E = -5V at the other end.

E and B are perpendicular  to each other inside the vacuum.

What is, then, causing the electrical current through
the vacuum? What is pushing the electrons along the beam?
Why is the grid voltage zero and stopping them dead ?
Why does the cathode have a fluctuating voltage?