New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1922-07-02
POtcntiOmeter
And RheOstat
Are Described
Both Needed in Conjunction
With Storage Battery and
Vacuum Tubes i'm Order
to Get Best Steady Results
One Controls Filamcnt
Other Controls Voltage in
Rcgcnerativc Circuit in
Which II Is Being Used

Why is :. that . vacuum tube can be
used for receiving and also for trans
hitting radio waves, Back Of this
question l.c two very important fac
tors which the radio Fan should know
because they aid him in making those
delicate adjustments 90 the modern re-
cciying set which insure complete sue
cess. Many times poor results with n
receiver are directly due 20 faulty ad-
justmcnt. rather than any defcc; in the
receiver itself.
To- order 90 perform the functions Of
receiver and trausmittcr the vacuum
tHbe D.. placed il "a circuit that IS prae-
tcailv identical. The degree Of bril-
Lane. with which the t.amcnt i5 burn
ing. plus small adjustment IN the
tcA'cr coil. SSH. flrn the tube from a
receiver into "a generator Of oscAlailng
currents. This fundamental fact should
always Boz borne DO mind.
ln fhc irst place The vacuum tube
81 in JOS he.t receiving condition when
Do ie Just below that oFciilatlne point,
.n4 III order 90 BE- % that condition the
rIauarf a. tho tghc should not be
burning very brightly The hlamcnt
current c.n bc controlled By the rhoo.-
STAT handle. which is supplied with
tolr sct.
Rhcostat T. Important
Now this itcos'at is very i'm
ror.aat piece az apparatus ~ ne re-
c.lrcr. and .'l function should be
understood clearly. because - viii not
ou.y enable sou % ret the best possible
results. hli lf viii also save you money
bv .cur'hen.nr tie life o. your cNpen-
f4rr vacuum tubes.
Tic majority u vacuum tubes nre
r0w produced Oh q quantity basis ana
ttc.r f.amcu's are designed 20 operate
nn lva volts aai one ampcTc. As the
standard storage battery Is rated AZ
Sis volts, tie rhcos'at Of SIX ohms
n placed in series with tho hlameri
.n order 70 prevent i's being burned
out ly excessive current, as well rs
fo permit adjustment.
The rAco.tat. .n addition 20 perform
ir. Chat important function, also pre-
tl.. che tlauerf from reaching tn"'
decree o. brightness which VIII pa
.t ln $3.50 orcliiat.rs condition when u
.f connected o. % rcgcrcTA'lvc circuit
Vic rltor'lt. however. must De 90 con-
sfructcd that 10 VII not heat up dan
cero1eir when 30 is 30 operation.
Rhcostat n Simple Instrument
There IS nothing mysterious about
tic ricoefaf. despite It's name. IL con
si.ts a. special metal Wire wound ~
.r.ral form around suitable frame
Ih metal has @ certain definite quar-
.tv bv which +. oIers q definite degree
of resistance 90 the passage OF an
electric current. ard. ~ course, inc
moro Of this wire there is IN the circuit
tr. -.r~a resistance viii De offered "a
ftc f1w a. currcu.--and that IS th'
..a. .. tho resistance IS made variable
ft.t YOU con control the current
flowing through tic Alamcnis OF yoHI
vacuum tube.
This degree Of control can be further
'rcro cd hy the addition % WERNER
rhco.taf. This IS smaller rheosta'
~ about one ohm resistance when u
ri.re4 in series with the other larger
rne..fat. Tho vcruicr should be "a
co. rtr.ctcd that it has smaller turns
hi order that closer adjustment car
m connection with the hlamcnt cir,
cp't o. .ac receiver, IL viii be observed
tnat .onc sets have potcntiomc'ci
across the storage battery. The iunc
..on az this instrument has been F'Ts
ngz-linc TO many fans and has peer
.hc cause Of repeated inquiries which
have reached ne.
Potcntiome,er Gives Control
LIZ. the rhcostat. there is nothing
mysterious about tho potentiometer
rrr is i.s operation difficult 20 under
send With potcntiomcter IN th'
circuit much better control IS ootained
and stcad.er results are given py 'h'
I'M the first place the potentiome,teii
81. .l.. "a resistance. so arranged th"'
+. c.~ D.. varied. blt the variation is W
~ entirely different manner 20 tnAi o.
tie fhcosta'. as BE- IFS operation. o'
r.c,ntlon purposes in rcf'"''"I'
,..r,irr. tube set the potcnuomeieI u
n,.eed across the storage battery Ter
m.na.s. IL has g total resistance o.
KS o.ms. Arranged across u IN som,
suitable manner is moving eohlae
.ll. or switch which enables in'
or.-a.or 10 vary the resistance IN th'
circuit where IL .s desired 10 nave
smaller current flow.
Potentiomctcr Regulates Voltage
Il en- be utilized TO place negative