New-York tribune., 1922-11-26
Ehinlble' Tube
Works Without
Any Battery
I.nous Scientist Describes
,a,esi Type of Vacuum
Tabe Before the Insti.
m,e Of Radio Engineers
,,.es A. C. Light Current
p,,,e Voltage Obtained by
Self Ratification; Tube
Has Hood Over Filanaent

.ovsi ystuuri tube which BIDS fair
s.latioaise radio receiving ap-
s.,ts. Isl Been developed and per-
s.,,ed M ii tie laboratories of the Cen
s. Electric Company at Schenectady
I. pr. 4 ". Hull. The details of this
sssrssble tube, which eliminates the
,.s.sity for "A' ana "B" batteries,
u described by the inventor in a
4. paper read before the Institute
sssdio Engineers.
ksuibed in simple language it is q
Il which will operate on the or
Ear alternating current light cir
Il isrough step down transformer.
10 designed that not only is the
|aztnt lighted in this manner, but
& satc circuit voltage is taken from
ssne source and usefully applied
|sgh the self-rectification of the
fan tube itself.
Iiile the tube has not yet been
|saly named, it has received the un-
|ta appellaticn of "The Thimbie
81 This title has been derived
IS It's peculiar construction, which
lists Of metal hood placed over
lament. Otherwise the tube fol-
L conventional design.
Transferer in Base
II It's assembled state the tube has
|ap-down transformer built into its
+. and the whole assembly can be
|ssniently held in one hand, The
ISN'T from the alternating light cir
SIS used to heat the .filament, which
B mrn indirectly heats UP the
Aable" placed over it. There arc
IS two gaps over which the electrons
4 pass inside the tube. Since the
sent is not actually in the active
Iassit Of the set, and is merely used
81 source of heat for the tfimble.
y slternating current hum is not
ktid in the telephones.
The we'll known valve characteris-
% Of the vacuum tube is taken
.iTsn!sge of in order to supply the
aga voltage necessary in the plate
atals Of the tube when used as a
ntic receiver. In this case the alter
aaliag current is rectified between the
lament and thimbIe, the latter acting.
ss an peeumulator of electrons, giving
Ing psats a constant positive potential
EltE respect to the thimble.
in describing the tube before the in
sHflfe d. Hull illustrated a number
Z circuits and one particularly in
aa9a u could DE ueed 10 bestS@ad-
lasge through the elf-recti6cation
lssafa, thus eliminating "B" bat
AN, This circuit is shown in the
'sgrsn accompanying this article. It
ll Be observed that in this diagram
aae is shown q filter circuit which
INSISTS of two condensers and re-
i'tante. This filter in conjunction
lth the peculiar action of the thinible
sas out the pulsations which result
'eIs the rectitieda alternating current,
q thereby reduces the hum which
igat otherwise mar the results in the
.teiyers.
fhimblc Acts, as Accumulation
Perhaps the best way to illustrate
e action of this novel tube is to
zen it to that of pumping station
I'd a reservoir. The pulsations caused
the pump IN its action have no effect
pen the res 2rvoir where the water is
loied, owing TO the surface area of
DC latter. The result is that when
Ester is turned on at q faucet along
he line connected to the reservoir
he how and pressure are practically
onstant.
II the pump were to be connected
.ireetly to the faucet, however, the
low OF water through it would be
cry spasmcdic indeed, due to the pull
a1ing action of the pump.
lhls Is practically the same thing
faf would happen if the filament of
ie ordinary type of vacuum tube were
'nnneted alp to an alternating SRrrent
arce through a step-down fans-
rmer, as many radio fans o&3Nn In
lisitiye turn of mind have already
severed by actual experiment.
With the introduction of the thin
!, or metal hood, in the Hull tube,
'xeyer, the action is more like that
the reservoir, because while the fla
ent still acts like the pump, the
lnbe becomes an accumulation OF
setrons.
Developed From Early Experiment
The development Of this tube fol-
sea that of an experimental design
acueed q few years ago in one of
scientific research laboratories
ssa 1t was desired TO have tube
&h would have uni-potential on
eleetron emitting surface. This
bot available in the ordinary type
'acuum tube, because one side of
. hlament is negative and therefore
si's more eleetrons than the other
se, s, which is positive.
me wonderful possibilities OF the
y ~ tube are easily apparent, espe-
.ly when the requirements of such
sSsfn circuits Us the super-generator,
! ! saper-heterodyne and radio-fre-
.slsy amphfication are taken into
,aaa where either 8 large
.aoef Of tubes are required, or else
cry ssfy high voltage B battery is
sss;s = sais connection it is, of course,
a. s'Sae 70 step up the voltage that
he y Placed on the plate circuit of
I ANY, Any tabe by the simple process
nth .alas step-up transformer
he Mg required voltage is obtained.
ons. Tying action of the tube con-
Irss respective of the voltage.
,nes. . waen the tube will make its
SEA eanee cannot be stated at the
siis.s i saae' Dr.. Hull, in his paper,
i Ssa .sa the possibility of developing
etsS @ ssses SO that they could be con-
!, ;alltectly TO the alternating cur
lsti,a circuit for purpose of
lvalss lls tne flament direct from the
sts. 's supply without the need of
sp'cowh transformer.