San Antonio light. [volume] (San Antonio, Tex.) 1911-1993, 1924-04-27
Radio Batteries
BY w. A. BRANNON, NJ. A.

, mum voltage on which it will operate.
Three cells connected in series make
total voltage of four and one-half.
The difference between three volts and
four and one-half volts is taken care
OF by the rheostat. Three cells con-
nected in series will furnish sufficient
current to take care Of as many as
three tubes. The series connection is
made by connecting the center termi
nal Of one dry cell to the outside ter
minal of the next cell. The center or
plus post of one end should be con-
rected TO the plus "A" of the receiv-
ing set. The minus post on the other
end of the battery should be connected
TO the minus "A" on the receiving set.
Use of the "B" Battery.
The "B" battery is used in the
plate circuit of the receiving set. In
this position its current changes con-
troll the action of the phone or loud
speaker and thus reproduce the pro-
gram that we hear over radio.
In the manufacture of "B" batteries
number of smaller dry cells are con-
nected in series to form blocks of twen
ty-two and one-half or forty-five volts.
1t is the voltage component of the "B"
battery which is of greatest impor-
tGnce for its proper performance. Uni
f0rmly maintained voltage when the
B" battery is doing the work is OBJ
tanned by using the best depolarizing
material which prevents the voltage
from dropping.
For obtaining high plate voltages
"B" batteries are connected in series
plus to minus. just as in the case of
single dry cells.
"B' batteries are of three general |
sizes: A small or midget size. a me-
dunn size and large size. The small |
size "B" battery is most practical |
in the portable receiving set. For |
stationary sets the largest size "B"
battery obtainable is the most eco
to use. The energy content |
of the large size "B" battery is much |
greater than that of the smaller sizes
and it will last correspondence longer.
When the "B" battery has given up
nearly all its energy its voltage drops
rapidly and signals become too weak
for satisfactory reception. Experience
has shown that after a "B" battery
has lost 30 per cent of its original
voltage. reception will be faint and
some "B" battery noise may develop.
When "B" batteries have reached this
stage they should be replaced by new
Ii" batteries in order to re-estabish
reception.
Use of the &C, Battery.
The &C" battery is used in the grid
'ircuit with simplifying tubes. Under
'ertain conditions the reception with
he &C" battery installed will be loud
r and clearer. The most important
'esult from the use of the &C" bat
cry is. however. the. reduction in the
consumption of the "B" lat
cry.
There has been a tendency to in
,rease the number of tubes used from
three TO five tubes, also to use a larger
plate voltage for loud speakers. The
increase in the number of tubes and
the plate voltage has made heavy
current demand on the "B' battery.
There have been n number of com
llaints that "B" batteries are not Civ
ng as long service as they did pre-
'iously. When you take the following
rto consideration you will unuersrano
Why:
A 45-volt "B" battery used with
201-A amnlifying tube will draw
ne-thotSandth Of an amperc from the
b" battery. If instead of using a
+5-volt "B" battery with 201-A tube
-ou double the voltage and use a 90
-olt "B" battery you increase the eur.
ent consumption to six-thousands of
IN ampere or six times as much cur
ent as is reatfred when a 4j-volt
Dattery is used.
II four and one-salf volt &C" bat
cry is used in the grid circuit with
| 9O-volt "B" battery the current
consumption is two-thousandths of an ;
lmpere or just twice as mucn as
where 45-volt battery is used in /,
with n 20-A tube.
Things TO Remember.
Here are few things to remember ..
bout dry cell batteries used in con-
lection with radio:
A dry cell battery has moisture and
subjected TO excessive heat will dry
ut and loose its efficiency. !