The Morning Tulsa daily world. [volume] (Tulsa, Okla.) 1919-1927, 1922-05-16
LESSON No 40.
The Storage Battery Ms Source Of
IiIamcnt Current.

When the fllament OF vacuum
tube N heated by an electric cur
rent. there is an emission OF cleo
irons or small charges OF negative
electricity. Up to n certain point
tho increase in current through the
filament causes an increase in TEN.
pcrature and consequently an In
crease IN the olectron flow. but an
excessive amount OF current Will re-
suit I'm burning out the filament and
the consequent destruction Of the
valuable properties of the tube in
the detection and amplification OF
the electric waves.
a storage or "a" battery. as Is
Is commonly known used as a source
OF flamcut current. Ia usually g.
volt battery OF the lead plate-sul-
phuric acid type and Is provided
with variable resistance for regu-
latiOn Of tho amount of current sup
piled 10 the filament.
The capacity OF this battery may
vary from SO to 100 ampere hours
the ampcre hour being unit de-
noting the flow OF one ampore
through circuit for one hour.
owing TO tho fact that the vacuum
tube when used in a receiving cir
cult requires only small amount
OF current. "A fully charged battery
Will supply current for n conslder-
able period. Tho amount OF cur
rent differs for various types OF
tubes and has range from 0.2 TO 1.5
ampcres, the proper value being re-
corded on the container In which
the tube is purchased.
Tho 6-volt battery consists OF 3
cells connected In series. that Is.
the positive terminal OF one cell Il
connected to the negative terminal
OF tho next cell, with the result that
tho total voltage of the battery Is
the sum Of the voltage OF the In
dividual cells. In this type OF bat
terry lead plates are supported In a
dilute solution OF sulphuric acid and
when current from an external
source is forced through the plates
and solution, a change takes place
In the plates and the battery stores
up n supply OF chemical energy.
when the battery IL connected to
the filament, this chemical energy
| In released In the form OF electric
current. when fully charged and
on open circuit. the voltage OF the
lead cell is slightly over two volts,
until the voltage falls TO approXi-
mately IL volts at which point It is
considered to be discharged.
The specific gravity OF the So
lutioner ,electrolyte IL a valuable In
dication of the condition OF U1e cell,
The normal specific gravity is usu-
auuy given on the name plate of
| the battery and when the battery
| is fully charged. should be from
1.215 to 1890. The battery should
not be discharged below point
whore the specific gravity is 1.l75.
| Due TO natural evaporation and
heating of the battery with a con-
sequent lowering OF the solution. It
is necessary to add distilled water at
intervals, so that the level OF the
olectrotype Is always at least one
half inch above the tops of the
plates.
The normal charging rate OF the
battery is marked on the name
plate and this rate should not bs
exceeded. as current Forced through
the battery In excess OF this amount
causes buckllng and short circui,ins
OF the plates, The battery shoult
he kept clean and the terminals free
from corrosion.
These instructions carefully fol
lowed will result I'm good service
and n considerable lengthening o
battery life.