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Nov. 26, 1946. '
Filed April 17, 1943
2 Sheets-Sheet 1
Nov. 26, 1946-
Flled Aprll 17, 1945
2 Sheets-Sheet 2
CECIL 5. lama/114M
Patented Nov. 26, 1946
a more!) STATES
aren't OFFICE‘
Cecil E. Brigham, East Orange, N. J., assignor to
International Standard Electric Corporation,
, New York, N. Y., a corporation of Delaware
vlfipplication April 17, 1943, Serial No. 483,378
In Great Britain December 31, 1940
2 Claims.
(Cl. 250—27.5) .
'This invention relates to electron discharge
apparatus and more particularly to electronicde
tectors and ampli?ers and to electronic oscillators
operable at ultra-high frequencies.
ator electrode and a control electrode, all such
electrodes being disposed in parallel relation. A
linear auxiliary electrode is also positioned on the
' side of the anode remote from the cathode and all
The invention comprises an electron discharge
device comprising a cathode and an anode, and
interposed. therebetween an accelerating elec—
trode, all of the said electrodes being of linear
the previously-mentioned electrodes are encom
passed by a cylindrical shield electrode. With the
auxiliary and shield electrodes at cathode poten
tial and the anode electrode at a relatively high
form and disposed in parallel relation; the said
positive potential with respect to the cathode, the
cathode being of circular cross-section and de 10 accelerator electrode at a less positive potential,
signed to be non-emitting over an area facing
and the control electrode at a slightly negative
the said accelerating electrode and symmetrically
potential, electrons emanating from the cathode
disposed thereto, whereby the proportion of elec
are accelerated towards the anode by the acceler
trons captured by the said accelerating electrode
ating electrode and a concentration of electrons
is reduced, the device being operated in the man
occurs in the immediate vicinity of the anode
whereby 'a dense charge region and potential
ner to be described below.
According to another feature of the invention,
minimum is set up in proximity to- the control
the cathode may instead be given a cross-section
electrode and anode. This space charge region
consisting of a ?gure with two straight sides fac
is augmented by electrons which miss the anode
ing the said accelerating electrode and including 20 in their original ?ight and come under the in
an angle which is less than 180 degrees in the
?uence of the retarding ?eld of the auxiliary
side away from the said accelerating electrode.
electrode and shield. Such electrons revolve or
According to another feature of the invention,
spiral about the anode before being collected by
a cathode of either type may be used in an elec
it, and the control electrode can, therefore, ex
tron discharge device for generating oscillations
ercise effective control upon this region so- that
comprising a cathode, an accelerating electrode
a very high transconductance is obtainable.
and a plurality of output electrodes, for reduc
Figures 1 to 6 are diagrams illustrating the re
ing the proportion of electrons captured by the
sults of experiments made on a rubber sheet
accelerating electrode, when the device is oper
model with arrangements of the kind described
ated as described below.
30 above. In these ?gures, C is the cathode, AC
The invention will be more clearly understood
the accelerator electrode, CG the control elec
by referring to the following detailed description
trode, A the anode, AE the auxiliary electrode,
and to the drawings, in which
- S'the cylindrical shield and E the envelope. The
Fig. 1 is a diagram of a type of electron dis-~
charge tube to which the invention is applicable,
showing the electron paths in the usual construc
tion and operation of such tube;
electron paths are indicated by broken lines.
It has been found that a large proportion of
the electrons emitted from the cathode are ab
sorbed by the accelerator electrode, resulting in
excessive accelerator current. This condition
must necessarily be very ine?icient and will affect
having an uncoated surface portion opposite the 40 the characteristics of the tube in regard to its
accelerator electrode;
slope and noise etc. due to inherent excessive
Fig. 3 is a similar view in which the cathode is
division of current. Experiments have indicated
that, as shown in Fig. l electrons emitted over
Fig. 4 is a similar view in which the cathode
an arc of 100°-120° of the cathode surface imme
has intersecting faces in alignment with the ac: 45 diately opposite the accelerator electrode are ab
celerator electrode arranged at an angle of 150°;
sorbed by the latter and never reach the anode.
Fig. 5 is a view similar to Fig. 4. with the oath
It has now been found that an improvement
ode faces at an angle of 130°; and
may be effected by leaving uncoated a portion of
Fig. 6 is a similar view showing a diamond
the cathode surface immediately opposite the
shaped cathode with said faces at an angle of 60°.
accelerator electrode over a substantial area, an
In the Bruce Patents Nos. 2,254,264 and 2,254,
angle of the order of 60°, as shown in Fig. 2, hav
Fig. 2 is a similar view showing the electron
paths when the tube is provided with a cathode
265 there is disclosed a detector or amplifying‘
tube comprising a linear cathode, and a linear
ing been found particularly effective.
anode, and interposed therebetween in the order
named proceeding from the cathode, an acceler
ploy a cathode of such cross-section that two ad
An even more e?icient arrangement is to em
jacent ?at sides facing the accelerator electrode
form an angle of less than 180“ on the side re
mote from the accelerator electrode. It has been
found experimentally, however, that the most
effective angles lie between 60° and 90°. A cath
this type which is shown in Fig. 7 the central
linear electrode l is maintained at a positive po
tential relative to the cathode c, and a plurality
of similar output electrodes 2, -3 operated sub
stantially at cathode potential are provided in
place of the anode electrode and accelerator elec
trode of the type of tube previously described.
By the use of the improved cathode constructions
described above the conduction currents to the
ode of rectangular or rhombic cross-section may
be conveniently employed with a diagonal of the
rectangle or rhombus in line with the line passing
through the centres of the linear electrodes.
Fig. 3 shows a rectangular cathode, while Figs,
4, 5 and 6 show arrangements in which the sides .10. central positive electrode I are reduced and the
e?iciency of the tube as a generator of high fre
of the cathode form angles of 150°, 130° and 60°
quency energy is increased.
What is claimed is:
Fig. 3 shows clearly that with a cathode of
1. An electron discharge device comprising a
square cross-section the flow of electrons to the
cathode and an anode, and interposed there
accelerator electrode is considerably reduced and
between an accelerating electrode, all of the said
that a greater proportion of the electrons emit
electrodes being of linear form and disposed in
ted by the cathode reach the anode. Tests on
parallel relation; the said cathode having two ?at
sample valves having circular cathodes showed
intersecting sides facing the said accelerating
an anode current of 800 micro-amperes and an
accelerator electrode current of 2.25 milliam 20 electrode and at an angle to each other which is
less than 180 degrees on the side away from the
peres for given conditions. Similar valves em
said accelerating electrode, and symmetrically
ploying a square cathode showed under similar
disposed thereto, whereby the proportion of the
conditions an anode current of 1.0 milliampere
electrons captured by the said accelerating elec
and an accelerator current of only 510 micro
trode is reduced.
amperes. Tests also indicated that the slope
2. An electron discharge device as set forth in
characteristics of the valve are improved by use
claim 1, in which said angle has a value between
of a square cathode construction.
60° and 90°. .
The above—mentioned Bruce patents also dis
close a tube having linear electrodes and in
tended for use as an oscillator.
In a tube of 30
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