Elenco Green Projects - Manual (Page 74)

Project #122 Slow In Flash Out
Hard To Crank
Set the slide switch to position B, and turn
the hand crank (HC). Notice how easy it is
to turn the crank, and how high the voltage
gets. A resistor in the pivot stand changes
the scale to 10V, so double the voltage
shown on the meter.
Set the slide switch to position C and turn
the crank clockwise. The crank runs the
radio, LED, horn, and motor. Notice how
much harder it is to turn the crank now,
and how the voltage doesn’t get as high.
The electrons slowly trickle into the 470 μF
capacitor (C5) through a 10K Ω resistor (in
the pivot stand) when the switch is in
position C. If you wait and let the capacitor
charge up it will flash nicely when you
switch to the left. If you are not patient, and
switch back too quickly your flash will be
weak.
Project #121
The crank is easier to turn when devices
that need lots of electric current do not
load it down. It is like you trying to throw
rocks - you can throw small rocks much
farther than you can throw heavy ones.
Patience is its own
reward. If you just wait a
little while, you get a
brighter flash. If you rush
your flash will be weak.
5V
See projects 1 & 3 if you need to recharge the battery (B4).
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