Bill wrote (over and over)
> >> I still ask for an explanation of why the filament or cathode in
> a tube has to
> >> be heated to receive the current flow. I've been asking this
> question for fifty
> >> years. Still waiting.
This is so easy. The filament/cathode has to be brought up to a proper
operating
temperature to emit electrons. When they are emitted, they can flow to other
electrodes in the tube's envelope, right? We measure the electron flux by a
variable
called 'current', which BY CONVENTION, is said to flow in a direction opposite
to
that of the actual motion of the electrons.
It's not that hard. It may not be what some folks like, but it's how it is.
Similar
questions can be asked about the electric field, and the direction of a
magnetic field
around a conductor which is carrying a flow of electrons [expressed as a
current].
73,
George T Daughters, K6GT
CU in the California QSO Party (CQP)
October 6-7, 2012
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