Elenco Green Projects - Manual (Page 40)

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Project #54 Two Speed Motor
Project #53 Sound Starter
Set the slide switch (S5) to position B. The
LEDs (D1 & D5) light but there is little or no
sound. Push the press switch (S2) to make
the sound work.
The voltage produced
will be lower when these
sources are running
something that needs
lots of current, because
the solar cell can only
produce a small amount
of current.
Set the slide switch (S5) to position B; the fan
spins and the red LED (D1) turns on,
indicating slow mode. The LED helps protect
the motor from getting the full voltage when
the slide switch is closed. Part of the voltage
goes across the LED and the rest goes
across the motor (M4).
Pushing the press switch (S2) bypasses the
red LED and now all the voltage is across the
motor, so it spins faster.
While the fan spins, carefully use you finger
to speed it up; the LED should turn off. As the
motor spins faster, its resistance increases
and voltage across it rises. Now there is not
enough voltage to light the LED until the
motor slows down again.
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See projects 1 & 3 if you need to recharge the battery (B4).