The Washington herald., 1922-05-28
Efficiency Varies
In Vacuum Tubes
Letter and Number System
Indicates Characteristics,
Instructions Show.

hoNc bCth as W
the characteristics of tubes listed
as CG and CIV followed by num-
bers. On June 1 the navy will sell
$4,000 vacuum tubes of various
types. The following explanation
OF these tubes applies to others
similarly designated.
1t would be helpful to keep this
data on hand. The tubes. which
will probably be bought by one or
two concerns a week from Monday,
will eventually be retailed. The
tubes will then be in use in thou
sands of radiophone sets. When
sold each tube must bear a label
describing the Limitations of the
tube as outlined by the United
States navy.
Characteristics of CG 1Is2 Tubes.
Transmitting-The CG 1852 is a
fve-watt tube and when used for
Transmitting purposes requires a
filament voltage of six volts. The
plate voltage used is approximately
800 volts.
Receiving-As most every one is
familiar with the performance of
the CIV 933 tube (also called the
VII and j. and the Sc 1444 (navy
tube manufactured by the Moor
head Laboratories). the perform
ance OF the CG 1852 tube as a re-
ceiving tube is expressed by a COM
parison with these types rather
than by giving the absolute con-
stants OF the tube.
In making these comparisons the
CG 1852 tube was operated, not at
its normal filament voltage, but at
six volts. At this voltage the fla
ment current is approximately Is
amperes. The reasons for operat-
ing the tube at this voltage are:
l. That satisfactory operation as
a receiving tube is obtained:
?. That IL saves the user the ex-
pense Of an extra filament bat
terry. and.
.. That the life of the nlament is
increased to approx mately 1000
hours.
Operation Described.
Operating the three types of tubes
at the same conditions. perform
ance characteristics were obtained
upon which the following state
ments are based:
Plate potential, twenty volts
(usual B battery voItage)-As an
oscillator the &C 1852 tube is about
Il per cent inferior to the CIV 933.
but about 81 per cent superior to
the SC l444.
As a detector of signals of mod
crate strength the CG 1852 is about
per cent inferior to the CIV 933
and about per cent inferior to the
Sc l444.
. AS an audio frequency amplifier
the CG 1852 is about I9 per cent
superior to the CIV 933 and l23 per
cent superior to the Sc I444.
The direct current between plate
and filament OF the CG 1852 is 566
per cent greates than that Of the
Sc l4A.
Plate potential, forty volts-As
an oscillstor the CG 1852 tube is
about II per cent inferior to the
CIV s33, but 81 per cent superior to
the Sc 1444.
As detector of strong signals
the CG 1852 is about 81 per cent
inferior to the CIV s33 and 5 per
cent inferior to the Sc I444.
AS an audio frequency amplifier
the CG 1862 is about 3s per cent
inferior to the CIV 933. but about
So per cent superior to the Sc I444
The direct current between plate
and filament is lis per cent greater
than that of the CIV s33 and 81 per
cent greater than that of the Sc
l444.
At eighty volts on the plate in
stead of forty the direct plate cur
rent is rs per cent greater than
that OF the CIV 933 and $50 per cent
greater than that of the Sc l444.
Summary Of Data.
The performance of the &C 1852
tube fa.rly closely approximates
that OF the CIV 933 as an osciIlator
and amplifier and approximates that
of the Sc l444 as a detector.
The DIRECT plate current of the
CG 1852 is much higher than that
of the CIV 933 or the Sc l444, but
the percentage difference greatly
Increases with an increase of plate
voltage. especially as compared with
the CIV 933.
TUBE Construction.
The CIV s33 tube is gas tube
having a coated filament and is
not similar to any commercial tube
known to the navy.
The Sc l444 can be compared
very favorably with the so-called
hard" tubes now sold for amateur
and experimental use.
The CG 1852 is about the same
for amplifying and "oscillates" as
the CIV 933. This tube is. how
ever, 123 per cent better than the
Sc l444 as an audio frequency am
piifer and as a deteCtor about |
per cent inferior to the Sc 14A.
The above description is charac-
teristic of the sample tubes tested.
However. no responsibility will be
assumed by the navy regarding the