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Патент USA US2136105

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NOV.8, 1938.
GJOBST
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2,136,105
ELECTRON DISCHARGE DEVICE
Filed Sept. 3, 1956
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Patented Nov. 8, 1938
UNITED STATES aren't
2,136,105
ELECTRON DISCHARGE DEVICE
Giinther J obst, Berlin, Germany, assignor to
Telefunken Gesellschaft fiir Drahtlcse Tele
graphic in. b. 11., Berlin, Germany, a corpora
tion of Germany
Application September 3, 1936, Serial No. 99,231
In Germany September 18, 1935
1 Claim.
(C1. 250—-27.5)
My invention relates to electron discharge de—'
vices intended for the production of oscilla
tions and more particularly to improvements in
devices of the negative resistance type in which
5 with high anode potentials less current is taken
by the anode than with smaller anode potentials.
The principal object of my invention is to pro
pressed, or on secondary electrons, ions or space
charge effects, or in the Barkhausen-Kura case
on a sorting out of the elects‘
in the present
case the variable penetrability of the anode with
respect to the electrons as a function of the
anode potential or electron speed is the means
relied upon for ful?lling the above condition.
vide an electron discharge device which can be
used for ampli?cation, recti?cation, mixing dif
There is produced by the thus presupposed
variable penetrability
l0' ferent frequencies or for producing oscillations,
and particularly to provide an improved type of
properties of the anode a ,
ll)
relationship between anode current and anode
potential in which there is ?rst an increase of
such device ‘having a negative resistance char
the internal resistance of the discharge plane
with increased penetrability and with further in
acteristic.
crease of penetrability of the anode as a function 15
.
‘
The novel features which I believe to be char15 acteristic of my invention are set forth with par
ticularity in the ‘appended claims, but the in—
vention itself will best be understood by refer
ence to the following description taken in con
nection with the accompanying drawing in which
Figure 1 is a diagrammatic representation of an
20 electron discharge device. embodying my inven
tion, and a circuit therefor; Figure 2 is a graph
ical representation of the operation of the de
vice shown in Figure 1 under different conditions
of anode voltage; Figure 3 shows a circuit ar
25 rangement embodying my invention; Figure 4 is
a graphical representation of anode voltage con—
ditions during operation of the circuit embodying
my invention and shown in Figure 5; Figure 5
shows another ‘circuit arrangement embodying
30 ‘my invention; and Figure 6 is a diagrammatic
representation of a modi?cation of an electron
discharge device embodying my invention.
By extending the ?eld of application of the
arrangement to very short waves where the
35 transit time of the electrons is of importance with
40
respect to the length of the period of the ac
tion, the more general formulation of above con
ditions applies namely that on the electrons that
are taken up- by anode the work
(t)
efKALVA
be ds
is done which is smaller than CVAO (where e sig
45 ni?es the elementary quantum, Vac the anode
’ direct potential,
@V_,<o__
O
as _E8t
50 the ?eld intensity as a function of time, or the
potential gradient, and dc the path element).
While generally the means for the generation
of oscillations is dependent either on the use
of grids, positioned ahead of anode and properly
~55 controlled, which ful?lls the condition above ex
of a rising anode potential, a reversal of the sign
of this resistance or a decrease.
The latter ac
tion takes place when the internal resistance is
already high due to additional means such as
a screen grid between the cathode and anode or
when working on the saturation point of the
"20
cathode ?lament. In case the resistance of the
cathode-anode discharge path is already statical
ly or dynamically negative due to some cause
or other, for example controlling the grid in
suitable phase, the means provided for the 25
penetrability variation as a function of anode
potential can be considered as adding these
properties and result for instance in a reduc
tion of the absolute value of the negative resist
30
ance or in an improvement of the ef?ciency.
It has been known since the experiments of
Lenard that thin foils of a metal with small
atomic weight for electrodes are the more per
meable the higher the electron speed. In this
manner the prior art was successful in having 35
electrons with high potential leave the vessel
through metallic foils that formed the closure
of a vacuum vessel against air.
The so-called
Lenard windows nevertheless have still consider
able thickness in order to be able to withstand 40
the difference in air pressure between vacuum
and atmosphere so that they have a proper
permeability only for electrons of very high
speed.
If however, as can be done with the
means available at the present state of the art,
optically transparent foils are used as anodes
inside the‘ tube, eliminating a mechanical stress
in above sense, the penetration of the anode is
achieved at relatively small anode potentials or
electron speeds. (See for instance German pat
tent 587,113, which likewise proposes the use of
such a thin metallic foil, however for‘ the entirely
different purpose of releasing secondary elec—
trons by the penetrating primary electrons.)
During the passage through the anode the elec
45
2
2,136,105
trons are subjected to an average velocity loss
which results in a heating of the anode, and
with smaller anode potentials or lesser electron
speeds the passage of the electrons through the
anode is prevented.
The greater the anode po
tential or speed of the electrons the greater the
probability of the electrons passing through the
anode and the smaller therefore the anode cur
10 rent.
The electrons passing through the anode
are caught by an electrode disposed behind the
anode: or the electrons may be re?ected in the
case of very short waves. In the ?rst case this
electrode may be a solid sheet or dense net and is
15
impressed with a slightly positive potential, in
the case of short waves it may have a negative
potential.
In accordance with my invention I reproduce
the atomic ?eld conditions existing in the interior
20 of metal foil electrodes by means of an arrange
ment of coarser type. Just as within the atoms
the electron paths are more curved and ?nally
are bound in the atomic bond, the smaller the
speed of the shot-through electron, in the same
way the electron paths are curved by means of
the arrangement shown diagrammatically in Fig
ure 1 in which the anode A consists of a pair of
interposed electrodes for instance one of bars ill
and the other of plates or slats II in alternating
30 succession. Between these electrodes there is ap
plied a constant potential difference and the
higher potential is applied to the larger electrode
or to the electrode comprising the plates. With
higher anode potentials and hence greater elec
35 tron speeds in the neighborhood of the anode the
electrons are de?ected relatively only a little by
this potential difference and ?y through the
anode. For the case where the anode potential
or electron speed in the vicinity of anode is
small,
the electrons are de?ected much more
40
strongly and so that most of the electrons move
toward the more positive part of the anode. An
electrode S positioned between the cathode K and
the anode A is positively biased with respect to
the cathode for accelerating the electrons from
the cathode to the anode.
In Figure 2a the path of the electrons from the
cathode K through the anode A to the plate P
is designated by the lines provided with the arrow
heads. It will be observed that under these con
ditions of high plate voltage that the electrons
pass through the anode without being de?ected to
any considerable extent. In the case shown in 2b
with the lower anode voltage applied, the elec
55 trons are de?ected from their path and are caught
and retained principally by the plate portions of
the anode electrode.
In the circuit shown in Figure 3 an oscillating
circuit comprising an inductance l2 and capacity
60 I 3 is connected between the cathode K and the
anode A. The ?xed potential di?erence between
the two electrodes forming the anode may be
established by a resistance and condenser combi
nation M or by a suitable source of voltage in the
form of a battery.
65
A type of feedback arrangement for producing
oscillations is shown in the circuit in Figure 5.
The plate electrode portion of the anode is con
nected to an intermediate point on the inductance
15 which is bridged by a capacity I6 to provide a
tuned circuit. A battery I‘! is connected between
the tuned circuit and the rod electrode portion of
the anode so that the rod portion is at a lower
potential. The voltage relationship on the rod
portion of the anode and the plate portion of the
75
anode is shown in Figure 4, which represents
the voltage relationship with respect to time dur
ing operation of the tube. The lower ?xed poten
tial E1 represented by the lower horizontal line
is that applied to the rod electrode portion of the
anode, the AC potential existing on this portion
of the electrode being represented by the curve
whose axis is the ?xed potential E1 applied to
this electrode. The higher positive potential E2 is
applied to the plate electrode portion of the anode
and the superimposed AC potential is shown as
the curve whose axis is the horizontal line repre
senting E2. While a battery i1 is shown in Figure
5, it is of course possible to substitute a resistor
and condenser combination such as shown in [4
of Figure 3.
While in the arrangements above the more or
less large penetrability of the anode is the result
of the ?eld relations inside the anode proper. I
may use an arrangement where the combination
of elements produces electron shadows and hence 20
electron beams, for instance diaphragms used in
cooperation with geometrically adapted construc
tions of the anode to furnish the desired effect. It
is for instance a well known fact that in larger
tubes the grid struts and wires form electron ‘
shadows on the anode whereby it may be directly
observed that the points of anode impinged upon
glow, while the ones not or less impinged upon
appear dark. According to the potential im
pressed on the grid causing the shadow and on 30
the anode, these light and shadow points have
different locations on the anode. By perforating
or cutting out those portions of the anode which
are primarily impinged upon with higher poten
tials I can produce the desired result. Factors to 35
be considered for the geometric development of
the tube depend upon whether the electron dis
tribution on the anode is produced by a shadow
throwing electrode of ?xed potential or of alter
nating potential coupled with the anode potential.
Particularly in the latter case the optimum perfo
ration or cutting out with respect to e?iciency
may be made only for de?nite operating condi
tions with respect to the amplitudes of anode and
grid alternating potentials as well as the direct
potentials. The experimental basis for the plac 45
ing of these perforations is obtained for example
with the aid of a model tube of the type here in
question which may be photographed for the
momentary values of the potential combination.
From these pictures are obtained the points to be 50
perforated or cut out for a certain purpose of ap
plication. It may be pointed out that the perfo
rations must not be-of such size that thereby
considerable ?eld variations, as compared to the 55
?eld of the non-perforated or cut out anode, may
occur at remoter distances from the cathode.
The purpose in view would thus not be gained for
the electron path would be de?ected too early in
the direction of the solid parts of anode.
60
A further embodiment of my invention is shown
in Figure 6. The electrons pass through a dia
phragm S having an aperture and to which is ap
plied a positive potential with a certain velocity
given by this potential and are deflected by the 65
?eld of the anode disposed parallel to the path of
the electrons passing through the diaphragm. If
the anode potential is large, the de?ection is
greater, and the electrons ?y through the perfo
rated part A’ in the vicinity of the slot and land 70
on the pick-up surface P located in the rear
thereof. With smaller anode potentials the de
?ection of the electrons by the transverse ?eld is
less and the electrons land accordingly on the
non-perforated parts of the anode A.
76
3
2,136,105
will be apparent that my invention is by no means
It may be added that the pick-up electrode last
referred to may also be impressed with an alter
limited to the exact forms illustrated or the use
nating potential of su'table phase‘ It is thus for
instance possible to modify the circuits in Figures
indicated, but that many variations may be made
in the particular structure used and the purpose
for which it is employed without departing from
3, 5 and 6 in such a manner that the pick-up
the scope of my invention as set forth in the
electrode is impressed with a potential having a
appended claim.
phase rotation of 180° with respect to the anode
potential. But is must not in turn in?uence the
control in the vicinity and inside the anode. This
and the passage of secondary electrons from the
one to the other electrode may be prevented by a
grid of suitable permeability and impressed with
?xed potential and positioned as a screen between
P and A’.
While I have indicated the preferred embodi
ments of my invention of which I am now aware
and have also indicated only one speci?c applica
tion for which my invention may be employed, it
What I claim as new is:
An electron discharge device having a cathode
and an anode permeable to electrons, said anode 10
comprising a pair of interposed electrodes of dif
ferent size elements electrically insulated from
each other and a second electrode adjacent the
anode for receiving the electrons which pass
through said anode, and a grid disposed between 15
the cathode and the anode.
GiiN'rHER JOBST.
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