Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 48

Here is a little experiment on the sidelines: If you remove the red LED from the circuit, you will get a small
solar charger for two AA NiMH batteries.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.24.
Circuit 25: Automatic solar light with battery
Setup information
Install the transistor and the two diodes as shown in Fig. 2.25. Install the three resistors and attach the AA
battery holders. The two jumpers come next. Finally connect the solar cell. Check the placement on the
board again and only then connect the batteries.
Experiment
It comes handy, if the solar light turns off during the day and automatically turns on at night. This circuit is
set up like our previous experiment. The solar current is stored in two batteries and would thus be available
50
Components required:
1 x solar cell, 1 x 2N3906
transistor, 1 x red LED,
1 x BAT 85 Schottky diode,
1 x 1N4148 silicon diode,
1 x 22 kΩ resistor, 2 x 1 kΩ
resistors, 1 x breadboard,
2 x NiMH batteries with AA
battery holders
Fig. 2.25: Automatic solar light
with battery