A VACUUM-TUBE VOLUNTEER USING A 6E5 TUBE

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000600390236-7
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 2
• Document Creation Date: December 22, 2016
• Document Release Date: October 19, 2011
• Sequence Number: 236
• Publication Date: May 7, 1951
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/10/19: CIA-RDP80-00809A000600390236-7
GONFIPENTIAL COt~FIDENTI~~_
CENTRAL IN I ELLIG"tivCE AGEiJCY REPORT
INFORMATION FPOM
FOREIGN DOCUMENTS UR RADIO BRGADCASTS CD N0.
SUBJECT
HOW ?
PUBLISHED
1'VHERE
PUBLISHED
GATE
PUBLISHED
Scientific - Radio, measuring instruments
Monthly periodical
Moscow
.?ul 1950
LANGUAGE Russian
[,.~~
DL [[NSL ~
iNl! DOCUM [XT CONTAINS IN [O RY ATION A[/FLTINO TN[ NATIONAL
01 TN[ UNITFO STAT[S WITHIN iN [- Y[A NIN6 O[-[l NIO NAO Ey`LATION
SOURCE Radio, No 7, 1950, p 59~
DATE OF
INFORMATION 1950
DATE DiST. ~ May 1951
NO. OF PAGES 2
SUPPLEMENT TO
REPORT NG.
A VACUUM-TUBE VOLTMETER. USING A :,ES TUBE
The attention of radio amateurs is invlted to a very simple form of
vacuum-tube voltmeter using a 6E5 tube which measures both alternating and
direct voltages (see appended diagrsml,
The circuit operates as foilows~ idhe~ the sliding contact of the poten-
tiometer Rl ie set st the uppermost position, the grid bias is zero and the
shaded area of the tube is maximum (zero of the voltmeter)a Tte voltage to
be measured is applied to the grid of the 6E5 tube eo that the bias becomes
negative, and the shaded area contractae At a given value of this voltage,
+iependin~r upoa the r?ctifier voltage, the shaded area narrows to a thin line
For example, when Ua = 250 v, the shaded area becomes a thin line when t~ne
grid bias reaches -8 vo If the voltage to be measured is less than -8 v, a
shaded area still remainse In this case, additional negative voltage is ap-
plied by changing the potentiometer resistance R1 until the shaded area be-
comes a thin linen Thus, it is passible to graduate the voltmeter scale by
the position of the sliding contact of the potentiometer Rlo
Alternating voltage is applied?to the same voltmeter terminals and rec-
tified by the grid-ca+hode section of the 6E5 tubed As a result, the grid be-
comes negative and the shaded area contracts to A certain limit -- depending
on the magnitude of the alternating voltage to be measurede By contracting
the shaded area to a thin line, using the potentiometer R1, it is possible to
graduate the scale in volts for alternating voltageo
This method is somewhat unusual, but it greatly simplifies the voltmeter,
? since the one variable -e=istance iu the cathode circuit serves both to zero
the voltmeter and to measure the voltageo Besides, this circuit makes it ~osai-
ble *o measure alternating voltage without additional rectifierso
CLASSIFICATION coNFIDENTIAII COI~FIDENTIAi ?
STATE NAVY NSRa DISTRIBlTION
ARMY (SIR Fa I
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 Sanitized Copy Approved for Release 2011/10/19: CIA-RDP80-00809A000600390236-7
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The errox of measurements i.s ^'.ose]y related to the variation of recti-
fier'voltagey and, therefore, a voltage regulator should be used in the cir-
cuito If there is no voltage regulator, the voltage in the circuit can be
regulated with the help of the SE5 tube itaelfo To do this, it is necessary
to see that the shaded. area has contracted to a thin line when the elide of
the potentiometer Rl is moved to the lowest positiono This can be done by
changing the line voltage, uaiug an autotransformei?e After this ie done, the
voltmeter can be graduated by the method described,
?T.se of +.he circuit described above is recommended to radio amateurs who
wish to coretruct a bridge from the description of Nekhayevskiy?s exhibit
(see, Radios No 2, 19!+91o It does not require additional parts and the re-
Sistor R] wR1 i1'_ =_erve for both regulating the sensitivity of the 6E5 tube and
measuring the voltage The author made, such a combination instrument to
~ueaeure? resistance, capacitance, and voltage, The range of measurements ie
0-? ~. dc, and 0-?~1 v ac for Lta= 170 v?
Since tY,e input resistance of the vo].tu:eter ie very high, it can be used
+,o mea~u_e voltage in any radio circuit and to check the operatiion of the AVC
linen The instrument can also be used as a resonance indicator when tuning
r..irr.:uite, The range of measurements ca.n be inr.reased by using a voltr.5e di-
videre
LAppended figure follows)
~~~"~l~F~T~~~
Sanitized Copy Approved for Release 2011/10/19: CIA-RDP80-00809A000600390236-7