MAKERFACTORY SOLAR EGG User Manual
SOLAR EGG
Build your own everlasting solar light
Discover the basics of photovoltaics
Exciting experiments with solar energy
SOLAR EGG
Using the sun's energy is exciting and environmentally friendly. It is
part of the Energy Harvesting task area because it "harvests" more
freely usable energy.
There are indeed many solar lights that turn on at night. But for these
completely different circuits are used, with completely different characteristics. Using a storage capacitor instead of the usual battery is
indeed innovative. And in the end, everyone can build their own personal
solar lamp and adapt their properties to their individual needs.
Caption: LED and solar cell
Experiment 2
In full sunlight, the solar cell delivers a current of about 20 milliamperes
(20 mA), which the LED can still tolerates well. Therefore the LED may be
connected directly.
For a series connection with two LEDs you need two double terminals. It
only works in bright light, otherwise the required voltage for both LEDs
will not be reached. Each LED requires a voltage of at least 2 volts (2 V).
SOLAR POWER
Experiment 1
In the first experiment, a green LED is connected directly to the solar
cell. The longer wire of the LED is the anode (A) and belongs to the positive pole (red) of the solar cell. The short wire is the cathode (K), which
must be connected to the negative pole (black) of the solar cell. The
brightness of the LED depends on the ambient light.
Cathode Anode
Caption: Series connection
Experiment 3
A parallel connection with two LEDs also works at low brightness
because it only requires a low voltage. However, both LEDs share the
available current. Two LEDs together produce the same light as one single LED.
BATTERY SUPPLY
For a battery supply with three cells and a total voltage of 4.5 V, a resistor must be installed in series with the LED. The resistance of one kilo
ohm (1 kΩ, colour rings brown, black, red) adjusts the current to about
2 mA. The LED can withstand up to 20 mA, but even at low currents, it
delivers considerable brightness.
Attention
Avoid short circuits! The two wires of the baery compartment must
never touch each other directly, as the high voltage can make the
wires hot or let the baeries explode.
Caption: Parallel connection
Caption: LED with pre-resistor
Attention
Aenon, you must never connect an LED directly to a baery,
because it could burn out immediately.
A test with the greater resistance of 10 kΩ (brown, black, orange) will
reduce the brightness. Even with the lower current of 0.2 mA, the LED is
still clearly visible.
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