Elenco Upgrade Kit SC500 to SC750 - Manual (Page 25)

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Use the LOW (or 10mA) scale on the meter (M2) and turn the slide
switch (S1) off. Vary the current measured on the meter by moving
your hand over the solar cell (B2) to block some of the light to it. If you
cover the solar cell, then the current immediately drops to zero.
Now turn the slide switch on and watch the meter again as you move
your hand over the solar cell. Now the meter current drops slowly if
you block the light to the solar cell. The 470
μ F capacitor (C5) is acting
like a rechargeable battery. It keeps a current flowing to the meter
when something (such as clouds) blocks light to the solar cell that is
powering the circuit.
Project #548
OBJECTIVE: To show how a capacitor is like a rechargeable
battery.
Rechargeable Battery
Project #549
OBJECTIVE: To learn about solar power.
Solar Batteries
Place this circuit near different types of lights and press the press
switch (S2). If the light is bright enough, then the LED (D1) will be lit.
Find out what types of light sources make it the brightest.
Solar cells work best with bright sunlight, but incandescent light bulbs
(used in house lamps) also work well. Fluorescent lights (the
overhead lights in offices and schools) do not work as well with solar
cells. Although the voltage produced by your solar cell is 3V just like
the batteries, it cannot supply nearly as much current. If you replace
the LED with the 2.5V lamp (L1) then it will not light, because the lamp
needs a much higher current.
The solar cell (B2) is made from silicon crystals. It uses the energy in
sunlight to make an electric current. Solar cells produce electricity that
will last as long as the sun is bright. They are pollution-free and never
wear out.
To learn more about how circuits work, visit www.snapcircuits.net or page 85 to find out about our Student Guides.