REPRINT OF ARTICLE FROM NATURE, VALVE WITH TROCHIODAL ELECTRONIC MOTION

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00926A000500030018-6
• Release Decision: RIPPUB
• Original Classification: R
• Document Page Count: 5
• Document Creation Date: December 14, 2016
• Document Release Date: April 23, 2001
• Sequence Number: 18
• Publication Date: August 17, 1948
• Content Type: REPORT

-OUNTRY Sweden
IN FORMATI TR `I
App ve J PI e1ease CIA-RDP80-00926A00050( M 8-6
CENTRAL INTELLIGENCE AGENCY
-DEJECT Reprint of Article from Mature , "Valve with
Trocboidal Electronic &fo rdfi"""'
'LACE
ACQUIRED
25X1 C
)ATE
ACQUIRED
THIS DOCUMENT CONTAINS INFORMATION Af1CT5N0 THE NATIONAL OETAIIIE
OF TNS INSTEP STATES WITHIN Til NEANINO OF THE ESFIONAGE ACT EO
C, S. C., SI ANO S2. AS 151!010. ITS TRANSMISCiON OR Till R2YSGA'F30N
OF ITS CONTENTS IN ANT YAMMER TO AN UNAUTHORISED PERSON 10 PRO-
NUTTED SV LAW. IEPED000TION OF THIS FOOS IS PROHIBITED. 110Yl
EVER. 1N5ORNATION CONTAINED IN SOOT OF THE room OAT BE UT+RI2ED
AS OEEMSO NECUSART RV THE EECEIVING AOENCY.
SOURCE DOC F TARY
DATE DISTR. 17 august 7-9443
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SUPPLEMENT TO
REPORT NO.
THIS IS UNEVALUATED INFORMATION FOR THE RESET
USE OF TRAINED INTELLIGENCE ANALYSTS
On file in the CIA Library is a reprint from Nam Volume 160, page 63.4
dated 1 November 1947, of the article "Valve with Trochoidal Electronic Lotion"
by Prof H Alfven and H Romanus. Prof Alfven, one of the authors of this paper,
is understood to have developed the Trochotron Tube.
RESTRICTED
X { PiAVi
CLASSIFICATION . Kill) naCTED
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 Approved For Release 2001/11/21 : CIA-RDP80-0092P40,00500030 1 --6
VALVE WITH TROCHOIDAL
ELECTRONIC MOTION
By PROF. H. ALFVEN and H. ROMANUS
Kungl. Tekniska Hogskolan, Stockholm
N a homogeneous magnetic field an electron with a
I velocity perpendicular to the field moves in a
circle. If an electric field is applied perpendicularly
to the magnetic field, the circle `drifts' with a velocity
which to a first approximation (electric field not too
strong) is
_ -H
v ,H X E.
The combined motion is a cycloid or trochoid. As
the drift is perpendicular to the electric field, the
circle in which the electron moves is displaced along
an equipotential line.
If a beam of electrons moving in cycloids or tro-
choids is produced, this beam follows that equipoten-
tial line on which it started. As in a valve an
equipotential line is easily changed and can be given
almost any desired shape, a trochoidal beam possesses
a high flexibility and can be used for many technical
purposes, for example, the construction of electronic
switchos and counters.
During recent years research on valves with
cycloidal or trochoidal electronic motion has been
carried out at this laboratory. The development of
the valves, which are called 'trochotrons', has been
carried out by G. IIambraeus and, especially, T.
Wallmark. Different circuits for the valves have been
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 Approved-For Release 2001/11/21: CIA-RDP80-00926A000500030018-6
worked out by Lindberg. Lundquist, Warring and,
Astrbm.
The type of valve mostly used at present is shown
diagrammatically in Fig. 1.
A homogeneous magnetic field (100-200 gauss) is
applied perpendicular to the plan of the paper. The
filament I omits electrons which are attracted by the
anode 2. Duo to the magnetic field, however, they
never reach the anode. Instead, a trochoidal beam is
formed travelling along rur equipotential line of the
electric field formed between the electrode 3, which is
held at zero or negative potential, and the electrodes
4 15, normally given positive potentials of 100-
200 volts. The whole current emitted (about, I rnA.)
is thereby received by the 'plate' 4.
If the potential of one of the olrx'trodos 5, 7, 9, 11,
or 1:3 (the 'guides'), for example, that of 9 is decreased
to about 20 volts or lower, the equipotential line
followed by the beam enters the box between 9 and
11. The current goes to plate 10. and in part also to
guide 9. If this is connected to the voltage supply
through a resistance R, the voltage drop in R will
maintain the low potential on the guide. Conso.
queritly, if once the beam in brought into a certain box
it remains locked up there. In other words, the
electron beam of the valve has the peculiar quality
that it is attracted to an electrode having a certain
voltago, but diverted from the same when the voltage
is decreased or increased. 't'his implies- a negative
slope in one part of the voltago-current charactoristic
of all the electrodes in the valve, that is, every
electrode may under certain voltage conditions act as
a negative resistance. The characteristic of an
electrode is shown in Fig. 2, whore . t R represents a
series resistance, giving the locking position C.
The groat flexibility of the trochoidal electron boam
also makes it possible to use 'two-dimensional'
electrode systems as in Fig. 3. If all electrodes except
0 are held at a high positive potential, the current
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goes to the plate 00. It may be switched, for example,
to the plate 21 by putting the vertical guide 2 and
the set of horizontal guides 1' under zero voltage.
A 10-box valve (see Fig. 1) is preferably used as an
electrical counter ('scale-of-ten'). The pulses to be
counted should be negative. They are applied to A,
which is normally hold at about 100 volts. Suppose
that the beam at the beginning is landing on plate 4
in the first box. A decrease of the potential of this
plate will displace the beam towards guide 5. Due
to the resistance R in series with this electrode, the
potential of 5 will immediately drop, so that the beam
is brought into the second box. The next pulse will
displace the beam from plate 6 to guide 7, which
through a potential drop transfers the beam to the
third box and so on. Finally,'on arriving at guide 15,
the beam is transferred to anode 2, and the anode
potential will drop in the same way due to a series
resistance, with the result that the omission from the
cathode is cut off for a moment. Hence the initial
conditions are restored so that the beam again goes
to plate 4. Thus the valve may he operated as a
cyclic switch. From the anode or one of the guides,
every tenth of the input pulses may be tapped to
another scale-of-ten unit or to a mechanical counter.
Neon lamps in series with the plates may be used to
indicate the actual position of the beam.
In this way the trochotron is used in electric
counters and chronoscopes. It seems also to be a
useful unit in calculating machines. A system for
pulse-time modulated multiplex telephony has also
been"
,,worked out, in which the valve is used as a
cyclic switch and modulator or demodulator simul-
taneously.
Detailed reports of the investigations are in
preparation.
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 Approved For Release 2001/11/21 : CIA-RDP80-00926A000500030018-6
Approved For Release 2001/11/21 : CIA-RDP80-00926A000500030018-6