Elenco Snap Circuits Motion - Manual (Page 60)

Build the circuit as shown. Place
the spout on the air fountain (AF)
and place the ball in it. Turn on the
slide switch (S1). The light motor
(M7) spins and lights brightly at
start, but then gets dimmer and
may even stop as the air fountain
gets going. The ball will spin
around in the spout and might rise
into the air.
If you replace one of the battery
holders (B1) with a 3-snap wire, the
light motor may not even start, and
the air fountain will barely move the
ball. The voltage is too low and
cannot push enough electric
current through the circuit to get
everything going.
Project 115 Light Start
Build the circuit as shown, turn on
the slide switch (S1). Both the light
motor (M7) and air fountain (AF)
are going. Place the ball directly in
the blowing air above the air
fountain. The blowing air should
balance the ball, so it floats in the
air and “dances”.
Occasionally the ball may become
unstable and fall out; just place it
back into the air flow. If the ball falls
out easily then reverse the
orientation of the air fountain.
If you replace one of the battery
holders (B1) with a 3-snap wire, the
light motor and the air fountain will
still operate, though you may need
to give the light motor’s fan a push
to get started. Performance will be
better with new batteries.
Project 116 Double Motion
! WARNING: Moving parts. Do not touch the fan during operation.
!
WARNING:
Moving parts. Do not
touch the fan during
operation.
-59-
Place the
spout on top
of the air
fountain and
the ball in the
air flow.
Spout
Motors need lots of electric current when
they start up, then much less when their
shafts are spinning at high speed (it is
harder to get the shaft spinning than to keep
it spinning). Compare this to riding a bicycle:
you have to pedal harder to get going, then
it’s easy to keep going at a constant speed.
Both the light motor and air fountain are
going at start, because both need lots of
electric current. Once it is blowing lots of air,
the air fountain needs less current, but that
amount is too little for the light motor. The
air fountain and light motor must have the
same current through them because they
are connected in series, so the air fountain
limits the current, “choking” the light motor
and making it shut down.
Compare this circuit to the preceding
one. Here the light motor and air
fountain are connected in parallel, so the
electric currents flowing through them
can be different, and they are basically
independent of each other. Each gets
what it needs from the batteries, and
both work properly. Another advantage
of connecting parts in parallel is that if
one breaks, the others keep working.
The advantages of connecting parts in
series (as done in the preceding circuit),
is that the circuit wiring is less complex,
and the batteries will last longer.
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