Can a purely thermonic cathod work?
hfeinstein at cox.net
Sun Sep 11 22:40:17 CDT 2005
In each and every vacumn tube I have ever seen the cathod is connected
to a source of
current. Therefore, I reason, the current must enter the material that
makes up the
cathode and launch the electrons that make it up toward to anode or
grid(s). The heater
must, likewise, raise the temperature of the cathode to make this
possible since a cold
cathode would never emit anything.
But wait! It this really the case, I wonder? We were all thought to
think of electrical
circuits through their hydrolic analogy -- wires as pipes, a battery for
a pump, a switch
for a valve. Gravity acted as resistace. While successful for some
circuits it might have
sealed in the wrong ideas for an electron tube.
What about a solid state theory of the cathode? Here a cathode might
be thought of as
a material that when heated boiled electrons out of its metal. Once
free the electrons are
attracted to the grid(s) and plate and begin the trip to those
elements. The cathode is not
a sprinkler supplied by the batteries but a metal that showers off
electrons when heated.
If this makes sense then you should be able take any electron tube and
re-engineer it so
the cathode uses a purely thermal energy source w/o ever connecting it
to a external current source. The tube should work just fine.
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