Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1916-10-07

of the above cases the relations be-
tween the resistance Of the lamp and
the resistance to be connected In
series with it is the same as the rola.
ton between the pressure acting Oh
the lamp and the pressure acting Oh
the resistance in series with the lamp.
Since the lamp requires pressure
of volts, the pressure acting on the
resistance to be placed In series viii
be the difference between the total
pressure, or "a volts, and the pres
sure acting on the lamp, or six volts,
which gives Is volts. The resistance
that must be placed - series With
the lamp will be equafst as many
times the lamp resistance as the pres
sure which is to act on the series re.
sistance is times the pressure acting
on the lamp. The pressure acting on
the series resistance in this case Is
three times that acting on the lamr
hence the value of the series resist.
ance must be three times the value
of the resistance of the lamp. The
resistance of the lamp is equal to the
pressure on 1t divided by the current
through 1t, or 6 divided by 4, or l12
omhs. Hence the value OF the series
resistance will be equal to times
11k, or Az ohms.
Pressure In Series
If two pumps be connected as SHOWN
in Figure 8, the pressure produced by
the other pump and the combined
pressures of the two pumps VIII ACT
upon the water circuit to which the
combination is connected. Several
pumps may be connected In this man
ner, and the sum of the pressures pro-
duced by the combination when they
are producing pressure in the same
direction around the circuit will be
equal to the total pressure acting in
the circuit. Thus, IL each OF the
pumps indicated in Figure Is pro-
duceing a pressure Of so pounds the
total pressure acting in the circuit TO
which the pumps are connected will
be equal to the sum of two pressures,
or 100 pounds. ~
If the pressure produced by the
pumps is unequal the total pressure
Is equal to the sum of the pressures,
Just the same. For example, il the
pumrs are producing pressure OF %
and rs pounds square inch. resPec-
lively, the total pressure acting on the
circuit to which they are connected
will be equal to Is plus 2E, or 100
pounds a square inch. II two men
shove against car in the same direc-
ton with a force Of 100 and l25
pounds, the total force acting on the
car is equal to the sum of the two
forces or 225 pounds. q.
Several electrical pressures may be
connected in similar manner to the
pumps, as indicated in Figure 8, which
represents two dry cells in series. II
the pressure produced by each Of the
dry cells acts in the same direction,
then the total pressure will be equal
to the sum OF the pressures of the two
cells, regardless of whether the pres.
sures produced by the cells are equal
or UNEQUAL in value Thus, IL the pres
sures produced by the two dry cells
are IL and Ia volts, respectively. the
pressure will be equal to II plus IA,
or &c volts. s..... ..... -
If a number of equal pressures be
connected in series so that they all
act in the same direction around the
circuit, then the total pressure will
be equal to the product of The number
of pressures connected together and
the value of one Of The pressures. For
example, If six dry cells, each produc-
ing a pressure Of Is volts, be con-
nected series, then the total pressure
will be equal to six times Is, or 9
volts. If ten men are all pushing on
car in the same direction and each
is pushing with the same force, say
100 pounds, then the total force acting
on the car will be equal to ten times
the force of a single man, or 1909
pounds. ..... ~.