Evening public ledger. [volume] (Philadelphia [Pa.]) 1914-1942, 1922-09-28

T'lilS "FIcming valve" rs it was called.
i was ndontod by tho telephone companies
and was placed at certain stations along tho
lines where tho currents IN the wires wcr"
diving down to such an extent that they
could nor be heard. ThcS" currents were al
I"wrd to travel through tn" hot filam"nt Of
tho valve and III" plates were connected 10
strong batteries.
These weak currents worr sufficient T."
have II controlling effect upon the clc"trnnS
thrown ont by the flnmcnt and. nS these
cirrtruns governed the amount Of rnrrent
flowing from the battery. the waive became
u hair trigger which Wa~ very easy to Op"r-
a'r. and il released battery currents 50
strong that they repeated the message and
~cnf il along the next stretch Of wire with
all "f tho power of the original human voice.
by means If this valve land limo telephone
communication bCcan" possible all IN" WY
from tn" Atlantic 10 the Pacific Ocean
through this method of boosting up the
strength of the signals about every "hO mlIcS
rJ,lIEN came lr. r." do Forest with his
/ cXpcrimontS and h" found that an even
greater trigger Hction could hc obtained by
mating II metal mesh which he called u
''Crid' hc'wceM tho plat" and tho tlInmem
and allow ing tho messages to strike TINS grid
and uSo it aS II trigger to control the flow
nf clrrtrons. u" Forests bulb was called u
'",hrec. clement" vHly"--thc elements being
tho tilan"nt, the plat" and the grid--anl il
is what wo know today as tn" "audion,
In his carly experiments De Forest was
much annoyed by tn" tendency which his
Nulh showed to cause Il loud hoWhng or
vhistlng in tho telephone. He put this
down ~ defect in construction, and all
lulbS which produced this result were ro-
icctcd by him. Then cam" n young student
from cornell named Armstrong. and HIS
study Of this bowling proved that instead of
hp ln
pruprrry which tho bulh had. He discovered
that when an audiOn bulb hu" I"d or
uhi~rl"d 4 was really creating power t>clf
and sending it on, all through the circuit
to which il was "onu"rtod.
Scientists now speak Of this action as
'oscilntion." which means that the original
weak current on th" grid releases u strong
current from the battery to tho plate. This
rurrcn, is f"d back with rrdoubi"d strength h
to the grid and releases still stronger cur.
rent from rhc plate. and 80 tn" current keeps
swinging back and forth between PLAY" nnd
grid nsing nS much power as can hc put
on the pint" by means Of batteries.
II is this ability Of the audon hulh ("
create its own oscillations and send them
out that has made possible the modern
miracle of br"adra>ting speech and music by
means Uf radio. Specially cOnstru"t"d bulbs
hnyr been built for this purpose, the design
being intended to permit stronger and
stronger batteries or dynamos 10 send their
currents 10 lh' plhI' hiiu 'htr''''' ,H'IIu OUT
signals that will travel farther and farther
through space. BY imprcssing about loo
Of "A hy power on the grid We can now con-
,rol several horsepower on the plate.
U,IIf. ordinary small amateur radio tec.
l. phono transmitting set uses from one tu
three hulhs each capable Of delivering five
watts The best clnss of amateur expert =
mental stations and many commercial sta.
INNS are ruuilppd with tubrs delivering fifty
,,tts and the modern hroadcasling stations
u.r from four I" eight big tubes, each ono
cupabIc uf delivering 80 waits.
'rhr tube now developed in Chlcag" will
send out 100, 600 watts, and this is sufficient
the dream of around the world radio tele-
phony capable of being accomplished.
All scientists nre watching with keen ~
terest the development Of the sudion bYlP