New-York tribune., 1922-08-27

DetectOr Cell
Is Sensitive
i EIccsrolytic Detecior Is
slightly Better Than Crys-
a: Abandoned w hen
he Vacuum, Tube Came
IL 10 Make and Operate
!. yery Stable and Doesn't
Require Amy Adjustment
fter II Has Been Set


{ 4. iii other arts, radio has its
.r;ss. and one of the most out
...s;nr of these is the mystery sur
.sinr the downfall Of the electro
:. assestor. This detector is of
4 .-.tIal iaterest to those radio fans
i. present own crystal receiving
!, sst yet have the opportunity and
!s-, ID make parts for themselves.
] Tst aa.strolytic detcctor is equally
4, ..asisvs as the best crystal, and, in
q, spiaipz, a little more sensitive than
,.ssa. II enjoyed "a brief reign in
~, .esl1u of radio, and just as iS was
#gss; 10 become the supreme ruler
"a, sseaum tube was brought forth
Mi II attention was promptly turncd
tie electrolytic to the newcomer
Il nspossibiiities of the vacuum tube
sYs 10 promising that all further ex.
8rssutation with the electrolytie
asN.sr was abandoned, and it quickly
into an Oblivion that it did not
3ssre. and which was not shared by
aystal detector.
4 smilar to Crystal in Operation
j, operation the electroiytic de-
ssf is, to great extent, very SINH
8.,s the crystal detectos and, in fact,
& ,cnstruction is almost identical.
Ira Is nothing difficult in its con
ss;tion or adjustment. 1t consists
IN snail glass or carbon cup, in which
III ,Isced few drops of 20 per cent
ssaon Of nitric acid. This acid forms
tlectrclyte. The electrode con-
Ara 81 . piece of very fine platinum
Sssa as "Wollaston" wire. which just
Air snder the surface of the acid.
u Ix circuit in which it is connected
u .zsetly the same as that for a
wsndum detector, in which dry
3a battery and potentiometer are
HI It's operation, however, is en-
~ different, The generally accepted
#ssy is as follows: That as soon as
n local current is applied from the
#aasiometer across the cell, bubbles
h around the platinum electrode,
@aDleteiy insulating it and stopping
M further flow in the circuit through
I'M telephones
# Theory of Operation
Wh soon as the electro agnetic
es received by the aerial pass
ggA the oscillation circuits, con-
ag of the particular type of tuner
M with the deteetor, the high fire.
sy current induced dissipates the
6Ales and restores the pathway for
M heal current to flow through, and
M Is recorded in the telephones in
usual manner, corresponding to the
@alsr form of the received signals,
sAsr It be voice or telegraph code.
III NJ sectrolytic cell is very fine
wsasof radio telephone signals,
sIfal ID bet, was one of the first de-
saHi b be used in the original ex-
fasaal work that was undertaken
III #hsdeveiopment " of telephony by
as I wireless as far back as 1907
aieastructing an electrolytic de.
~ practically the same form car
iza as that now employed for the
Pc detector. The arm which car.
iae cats whisker for the galena
used for the electrolytic de-
a There is this very important
iten, however, that the screw
Ning the platinum wire should have
thanded thread of very fine gauge
nat an extremely small distance
covered by one complete turn.
i Wire Must Only Touch Acid
xss is very important, because il
e than the tip of the platinum is
asEsed in the acid the detector will
@ operate as efficiently as it will
a the wire is only just touching,
platinum wire should be fused
the lower end of the screw, and
nth.
Wollaston wire is used it will be
Had 70 be coated with silver in order
pimit easier handling. This silver
aung can be removed by a very
eng solution of chemically pure
4llochloric acid, or else it can be
oyed BY dipping it into small
aant of mercury that has been
yea over Bunsen burner.
n iae cup which holds the acid can be
F glass or high-grade carbon. In
Svs'om OF this very small piece
gMnhum, about three-sixteenths of
asa square, should be placed, and
should be connected to one of the
.as posts of the detector; the
n holding the platinum wire, of
sl peing connected to the other
Ihree-Cell Dry Battery
local battery used in con;pnc-
sMa THIS detector should consist
S ary cells, around which should
ss1ea Q 3,O00-ohm potentiometer.
FAN nephones used in conjunction
eiectroiytic deteetor may have
se as low as seventy-fve ohms,
a,s ~ ordinary 2,000-ohm radio tele-
SR be used without any diff
aaatsoever. The main point
s,a as telephones is that they should
6, INSTRUCTED and sensitive. An
~! 4goftant point that must be
sss that the positive pole of
@ battery must be connected to
ssffylng the platinum wire.
a. a before, the detector will
,s sstlS'e IN a sensitive condition
very faintest portion of the
vuehlng the acid, and this is
ae reasons that the electrolytic
apandoned because Of the diff
ssstihg that adjustment.
wire Fused in Glass
ume Of its abandonment, how
au been discovered that if the
sire was fused into glass and
!. GOWN SO that very minute
y was exposed the electrode
De solidiy immersed in the
,s vac detector left in rugged,
condition. This entails a
Is. trouble in making the de-
- ~ is trouble that is amply
me results obtained.
saanss s.lnani is fused into glass in
asr the detecter can then be
ssss sensitive condition by screw
sv;s she eiectrode into the acid
tag Y there. 1t will then be
slos, vpeTate perfectly under all
ssa Mistneut any trouble whatso-
~, sstnout any bother about re.