This circuit illuminates 5 LEDs when there is not sufficient sunlight for the solar panel to charge batteries.
The LEDs will automatically turn on and draw voltage from the batteries when the solar panel can no longer convert sunlight to DC voltage.Technical Specifications:
- Power Source: 3 rechargeable double AA batteries (not included)
- Power consumption: 2.5 mA (standby), 80 mA (working)
- Recharging circuit: Built in solar panel
- Solar panel: 4 VDC, 60 mA
- Intensity adjust: potentiometer
- PCB dimensions: 2.39 x 1.70 inches
This circuit consists of two parts, the charger and sensor.
When the solar panel is facing sunlight it will convert the suns energy to DC voltage and run through transistors 1 and 3 charging the rechargeable batteries.
The sensors are activated when the photo-transistor (solar panel) does not receive sufficient sunlight the internal resistance becomes greater triggering transistor 5 to light all LEDs.
Illumination intensity is controlled through transistor 2 and variable resistor 1.