On Sat, 29 May 2010 16:58:52 -0700 (PDT), walt wrote:

Although I understand that induced
current results from a moving charge, I'm not as comfortable
discussing the Rp issue in terms of charges as I am with currents, so
I'm having a little difficulty in coming to grips with Rp while
reviewing the paper.

Hi All,

For others, there might be wonder at the meaning of induced or
inducted current - or convection current for that matter. It would be
useful to expand here in a new thread.

First. In the interval between cathode and plate, there are only
electrons. In other words, there are no conductors as are found
everywhere else.

Second. When an electron flows between the cathode and the plate,
charge is moving. By convention, this is called current. It goes by
a special label - convection current.

Third. The interval between the cathode and plate is part of a
complete circuit that travels through the power supply, returns to
ground and rises from ground to come to the cathode.

Fourth. For charge movement through the interval between cathode and
plate, there is exactly the same charge movement through ALL wiring
connecting the plate to the power supply, wiring from the power supply
to ground, and wiring from the ground to the cathode.

Fifth. The charge movement throughout the wired circuit, by
convention is called current. it goes by a special label - induced
current.

The distinction between induced current and convection current is
found in their transport media. One is metal, the other is vacuum.
The convection (like convection heat) is electron movement in space
which induces current in the wire. This induction is NOT like
transformer induction. It has absolutely nothing to do with magnetic
linkage. We could call it induction if the entire circuit were
composed of wire. That is, the movement of one electron "induces" the
movement of another electron.

Similarly (and tipping my hand about reflected waves), an extra
electron push in the wiring will induce an electron in the tube to
move. The current is inextricably locked in a dynamic flow. There is
no new physics in this anywhere.

So why two terms? The necessity of this seemingly obscure point is to
exhibit how heat is formed, and why the plate of the tube is a
literal, real resistor in this circuit. Very few correspondents (read
none but myself) to this board dwell on this, and they end up
dismissing the real resistance of this specific and consequential
source as a mathematical fiction suitable for only milliwatt signal
generators.

73's
Richard Clark, KB7QHC