Elenco Green Projects - Manual (Page 65)

Project #103 Small Energy
Conversion
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Build the circuit shown, and place the solar cell
(B7) in sunlight or close to an incandescent lamp
for a few seconds. The red LED (D1) should light
briefly. The solar cell converted some light
energy into electrical energy, which was stored
in the 470
μF capacitor (C5).
Press the switch (S2). The horn (W1) makes a
brief sound. The electrical energy in the
capacitor was converted to sound waves
(variations in air pressure) by the horn.
P art B: Replace the horn with the yellow LED
( D5). Now the yellow LED converts the energy
stored in the capacitor back to light.
P art C: Replace the yellow LED with the motor
and wind fan. Now the energy stored in the
capacitor is converted to mechanical motion by
the motor. The fan will not move very much.
Project #104
Mechanical
Energy
Conversion
Replace the solar cell with the hand
crank. Now you can convert
mechanical energy to electrical
energy in the capacitor, then to
sound, light, or motion.
Project #102 Energy Conversion
Set the slide switch (S5) to position B. Some of the chemical energy in
the battery becomes electricity, which is converted into mechanical
energy of motion by the motor (M4).
Now set the slide switch to position C. Some the mechanical energy in
the motor generates electricity, which travels to the red LED, where it
becomes light.
Part B: Replace the motor with the yellow LED (D5) or the horn (W1).
Set the slide switch to position B. Now the chemical energy in the
battery becomes light energy or sound energy (air pressure variations).
Part C: Replace the battery with the hand crank. Now you can convert
mechanical energy of motion to chemical energy in the battery, then to
motion, light, or sound.
+
The capacitor stores
energy as an electric
field, similar to the
magnetic field of a
magnet. It can only
store a small amount
of energy in this way.
See projects 1 & 3 if you need to recharge the battery (B4).