Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1916-10-14

care Tor ana repair any and all OF the
electrical features OF his car, no mat,
ter what make or model II may be.
- With the ground work well laid b.
etudy OF the early portion of the Sc
: ries, the reader will be able to thinl
electrically. and a tangle of wire un
der car or tangle OF lines on ;
wiring diagram will become clear
The articles are reproduced by per
mission from Motor Age, for which
they are prepared by David Penn
Moreton and Darwin s. Hatch.
II water circuit is composed oi
two pipes and they are connected III
the manner indicated at A and b In
Figure 1, they are said to be connect
ed In parallel or multiple. There are
two paths In which the water may
flow in passing along the circuit from
the point A to the point B, and just as
much water Is returning to the pump
in a given time as Is leaving It, The
quantities of water passing through
the different pipes I'm a given time or
the currents OF water In the different
pipes connected In parallel are not
necessarily eqIal unless the resist
ances OF the different pipes are the
same The water is not used up In the
operation OF such circuit
An electrical circuit composed of
two or more different wires OF per
s haps different sizes, lengths and ma
terial, and connected as shown in Fig
ure 2, is called a multiple or parallel
circuit. In this case there are as
many paths for the electricity to flow
through in passing from the positive
terminal TO the negative terminal,
through the circuits outside the bat.
terry, as there are different wires In
parallel Just as much electricity is
returning to the battery in a given
time as is leaving the battery. The
quantities of electricity passing
through the different paths In one sec.
ond or the currents in the different
paths OF the parallel circuits are not
necessarily equal unless the resist
ances Of the different paths are the,
same Just remember that the cleo.
arieity Is not used up in the opera
ton OF such circuit.
A parallel water circuit ie found in
the operation of the cooling system
OF q motor car engine, as shown in
Figure 3. In this case the water JAG.
kets of the four cylinders are all con-
nected in parallel, and the pump
forces the water through the water
jackets and radiator. The current OF
water through the pump and radiator
is the same and equal to the combin-
ed currents through the four water
jackets. The currents in the different
water jackets are not necessarily equal
unless the opposition offered to the
flow of water through the different
jackets is the same in each case. IL
is obvious that II the water jacket
of one cylinder offers a greater op-
position to the flow OF the water than
the other water jackets there will be
a smaller current through this jacket
than through the others. The water
Jacket Offering the greatest opposi-
ton to the how of water will have
the smallest current, while the water
jacket Offering the smallest opposition
always will have the largest current.
The current in the remaining paths
will have value somewhere between
the above maximum and minimum va.
lues.
When the headlights on q motor
car are connected, as shown in Fig
ure 4, they form a typical parallel
electrical circuit Just as much cleo
tricity returns to the battery in a
given time as leaves the battery. The
current in each of the lamps is not
necessarily the same. Remember. the
electricity is not consumed in the
lamps.
Resistance Of Parallel Circuits
Since the resistance offered by al
pipe to the free flow of water through
il decreases with an increase in the
size Of the pipe, the length remaining
constant, il Is evident that the resist
ance offered by two pipes connected
in parallel will be less than the re-
sistance of a single pipe. If the two
pipes are of exactly the same size and
length they will, when connected in
parallel, offer enc half of the resist
ance to the flow OF water through the
circuit that is offered by a single
pipe.
For convenience the two pipes, as
shown in Figure 5, might be consid-
cred as being equivalent to single
pipe, as shown in Figure 6. whose
length is the same as that of each of
the two pipes and whose area is equal
10 the combined area of two pipes,
which will be twice that of either pipe,
since the pipes are equal in area. The
resistance OF this large pipe, which is
TO. replace the two smaller ones, will
be one-half of that OF either of the
single small pipes, since its area is
equal to twice the area of either OF
the two small pipes.
Two wires of the same size and
length and of the same material will,
when connected in parallel, offer re-
sistance which is equal to the resist
ance of wire OF the same material
and having the same length but hav-
ing an area equal to twice the area of
either wire. Thus the resistance OF
two wires of the same dimensions and
material will offer, when connected in
parallel, one-half of the resistance of
either wire alone ANY number of