Cold Cathodes & UV

Jerry Wayne Decker ( jwdatwork@yahoo.com )
Mon, 19 Jul 1999 12:25:34 -0400 (EDT)

Hi Folks!

I was looking for something the other day and came
across this interesting comment that got me thinking
about Moray's 'cold cathode' tubes that he claimed he
used in his circuit to produce upwards of 50,000
watts. I keep thinking there is something about this
that is being missed, so collected some additional
information about cold cathodes, how they work and
their uses;
------------
...From a magazine article in Popular Electronics, Dec
1993, 'What are Electrons made of?', page 40;

A few years earlier, in 1887, Heinrich Hertz
(1857-1894) had been experimenting with a spark gap.
His apparatus consisted of a metallic cathode
(electron emitter) and anode (electron absorber)
suspended in a vacuum bottle.

When he connected a battery across the electrodes,
Hertz found that an electric current would flow
through the vacuum, but ONLY WHILE THE SPARK GAP WAS
EXPOSED TO LIGHT, in total darkness, NO CURRENT WOULD
FLOW.

In 1902 this phenomena was further investigated using
a circuit similar to the one shown in Fig. 2A. It was
found that high-frequency (ultraviolet) is MUCH BETTER
at liberating electrons from the cathode's surface.

In addition, no electrons are ejected if the frequency
is decreased below a certain value, REGARDLESS OF THE
LIGHTS INTENSITY.

When illuminated by ultraviolet light at different
intensities, a negative voltage must be applied to the
sparkgaps' anode to completely stop all current flow.

In other words, ULTRAVIOLET LIGHT EJECTS ELECTRONS
FROM THE CATHODE with enough kinetic energy so that
they can still overcome an opposing battery potential
(a small negative electric field). This phenomenon
was named the photoelectric effect, and Hertz is
credited with its discovery.
---------
http://zebu.uoregon.edu/~js/glossary/photoelectric_effect.html

"...the observed phenomenon was that the current flow
was basically constant with light strength, yet varied
strongly with the wavelength of light such that there
was a sharp cutoff and no current flow for long
wavelengths....Each photon of blue light released an
electron. But all red photons were too weak. The
result is no matter how much red light was shown on
the metal plate, there was no current."
---------
http://news.chemicalonline.com/product-releases/19971202-374.html

"When vacuum system pressures are very low, cold
cathode sensors take time to start measuring the
pressure. IgniTorr releases photons into the cold
cathode sensor, starting and maintaining the
ionization process in the sensor. This allows for
constant pressure measurement. Using the cold cathode
starter reduces starting times from hours to minutes."
----------
http://eet.com/news/97/947news/emitter.html

"The High Efficiency Electro-Emission Device (Heed)
features a metal-insulator-silicon (MIS) diode
structure. In a demonstration by the company, Pioneer
engineers applied 90 V on the device and 5 kV to
accelerate electrons. Using the regular phosphor
normally used for CRTs, the Heed emitted a dazzling
light with a brightness of 80,000 candela per square
meter. No other cold cathode devices, such as field
emission devices (FEDs), achieve such brightness. "
-----------
Philo Farnsworths interest in the effect (w/patents);

http://www.ticnet.com/bertpool/philo/philo.htm

"Of the forty or so patents which led up to patents
3,258,402 - Electric Discharge Device for Producing
Interactions Between Nuclei, and patent number
3,386,883 - Method and Apparatus for Producing
Nuclear-Fusion Reactions, it can be seen that only two
or three of these Farnsworth patents do not utilize
secondary electron emission in some way.

...the Fusor - the only fusion reactor ever designed
and operated at better than break-even efficiency!

...Farnsworth's Fusor produced neutron counts measured
in the billions-per-second. No other fusion device
built, even 30 years later can match this
performance."
------------
http://www.korry.com/bklight6.html

"High energies are needed to eject electrons from the
cold cathode. The voltage drop (cathode fall) between
the plasma discharge region and the cathode is about
150 V. The high cathode fall pulls ions from the
discharge. Energetic mercury and argon ions striking
the surface of the cold cathode release electrons in a
process known as "secondary emission". The secondary
emission causes sputtering from the cathode and can
quickly erode the structure away. To moderate
sputtering, a relatively high gas fill pressure is
used in cold cathode lamps. This high lamp pressure
will lower lamp efficacy. In addition, the higher lamp
pressure results in a higher lamp ignition voltage
which impacts the power supply design.

No power is used to heat a cold cathode, but a large
fraction of input energy is lost in the cathode fall
to maintain the discharge. Therefore, cold cathodes do
not need an initial power investment (as is the case
for hot cathode filament pre-heating), but have lower
efficacy than hot cathodes."

===

=================================
Please respond to jdecker@keelynet.com
as I am writing from my work email of
jwdatwork@yahoo.com.........thanks!
=================================
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