Elenco Green Projects - Manual (Page 16)

-15-
Project #4
Assemble the pivot, mount the solar cell (B7) on it, and place it in the
circuit as shown. Place all the parts with a black 1 next to them on the
clear plastic base grid first, then parts marked with a 2, and finally the
parts marked with a 3.
Connect the solar cell to the circuit using the red and black jumper wires.
Place the circuit so the solar cell is in bright sunlight or close to an
incandescent light bulb. Set the meter (M6) to the 5V setting.
The meter is measuring the voltage produced by the solar cell. Adjust
the position of the position of the solar cell on the pivot to see how the
voltage produced changes depending on the angle to the light source
and the brightness.
Position the solar cell to make the highest voltage you can. Now push the
press switch to run the yellow LED (D5) with the solar cell. Notice how the
voltage produced drops when the LED is connected.
Note: The voltage produced is actually twice that shown on the meter
(so a 3V reading is really 6V), because a resistor in the pivot stand is
changing the scale.
Part B: Replace the yellow LED with the red LED (D1) and press the
switch. See how much it affects the solar cell voltage.
Solar Power
+
+
5V
In the preceding circuit, replace the
yellow LED (D5) with the motor (M4, in
either direction) and place the wind fan
on it. Now press the switch and watch
how the voltage changes as the solar
cell runs the fan. Depending on your
light source, the fan may need a push
to get started or may not work at all.
Project #5 Solar Motor
The motor needs less electricity from the solar
cell as it speeds up, so the solar cell voltage is
higher as the motor gets faster.
5V
Your solar cell makes electricity from
sunlight, but only a small amount. In
bright sunlight it produces a voltage
of about 7V, but this is reduced when
lots of current is flowing. That is why
the voltage drops when you connect
the yellow LED.
ASSEMBLING PIVOT STAND
1 2 3 Place base on
flat level surface. Snap ball
on pivot
post into
pivot top.
Insert post
into base.