Velleman EDU02 - Manual (Page 9)

9 www.vellemanprojects.com
Required parts: Solar cell, 100 ohm resistor (brown black brown gold), yellow led
R1
100
LD1
orange
E1
SOLAR CELL
How it works: A closed circuit is
required to make the current flow.
Current flows from the (+) of the
solar cell trough resistor to the (+)
of the led and via the (-) of the led
back to the solar cell. On a sunny
day, the solar cell will generate 3..4
volts. The led only requires 2 volts
to operate. Resistor R1 converts
the excess voltage into (a little)
heat, hereby protecting the led from
damage.
Time to experiment:
What happens when you swap (+) and (-) of the led?
What happens when you replace the 100 ohm resistor with
a 47000 ohm resistor (yellow purple orange gold) ?