Indiana daily times. [volume] (Indianapolis [Ind.]) 1914-1922, 1922-03-29
Learn Radio Symbols Today
RADIO
BY r. @. ENNAN

1.-THE radio plague" which has taken
the country nearly over night, was dis
cusss I'd by Charles P. de Voss, secretary
and treasurer of tne Capitol Radio Sup
ply Company, at a banquet last night of
the Junior Chamber of Commerce at the
Chamber of Commerce.
Mr.. De Voss spoke Of the great amount
of space being devoted to radio by all
leading papers and magazines and of the
tremendous response Of the public to
radio.
Mr.. De voss said in part:
"You all have heard of crystals. cleo
trolytic and vacuum tube receivers. In
the crystal, certain minute particles of
the crystal are very sensitive to the cleo
irons, transmitted from the sending sta
ton at the rate of 300,0 900. 900 per second
or 1S6, 900 miles per second, and through
the use of added inductance and tele-
phone receivers the messages are re-
celved. Using the eIectrolytic receiver in
stead Of the crystal, the chemical action
of the cell sets up a sensitive current
which is very sensitive TO the waves
passing through the atmosphere.
with the three-electrode acuum tube
which is an simplifying detector, the OPP
Grafton OF the three-electrode vacuum
tube can be clearly understood by most
OF the men knowing something about
electrics in that there are two distinct
circuits, an input and an output. The
input consisting of a grid and a anne
the output Of the flament and the plate.
Before going further the vacuum tube
is a fOur-element instrument consisting
OF a flament in the center Of the tube
around which there is n grid and around
the grid there is n plate and the assem-
bly, in turn is mounted in a vacuum tube
looking for the world and all like an
electric lighting bulb.
Getting back to the action Of the Il h
when the flament is heated to an In
candescense It discharges negatively
charged eleCtrons and these are drawn
across the flament plate space by the
positive potential applied to the plate
by the B battery. This stream of cleo
irons really constitutes an electric cur
rent through the evacuated space be-
tween flament and plate and is eI-
tensively sensitive to any electrical in
huence in its vicinity.
The grid Is inserted in this space and
its potential normally is negative with
respect 10 the potential that the space
would have In the absence Of the grid.
The amount Of the e~lectron mission
from the flament IS dependent on the
area Of the flament. its temperature, the
positive voltage applied to the plate, and
the voltage applied to the grid.
9TH remarkable properties OF the
hree-electrode vacuum tube nv n detectOr
are due 10 the fact that any change I'm
grid voltage results In a multiplied
change In the plate current over that
which would result II the change in the
grid voltage were applied directly 70 the
plate. The ipput energy impressed
across the nlaTent and grid results IN
a magnifed change in current in the
plate or output circuit.
Summing It all up while talking with
a few young men down in the lobby,
some one advised that a certain young
man was about TO invest IN q receiving
set so that he would not have to roll out
on Sunday mornings TO 20 10 church, 40
that he would only have 10 turn n few
diais and he would he listening in on the
sermon. This, in all probabilities. is n
little far fetched.
"a short time ago while IN the labora-
tory Of n young married man he got to
Kidding me about some good looking
little girl and accidentally I passed a
cutting remark, last hut not least, the
transmitting station behind his back was