FA1007 Solar Automatic Night Light

The FK1007 kit is a small solar cell circuit designed for educational
purposes. It is suitable for studying and learning the basic principles of solar
energy systems and automatic light ON-OFF control.
Overall Operating Principle
- Daytime: The solar panel generates electrical energy to charge and store
power in the battery.
- Nighttime: When there is no light falling on the solar panel, the panel
stops supplying voltage, causing the LED lamps to turn on automatically.
Technical Specifications
- Battery supply voltage: 3.7-4.2 V
- Maximum circuit current consumption: Approximately 25 mA
- Solar panel: 4.2 V, 60 mA
- Battery: Li-Po 3.7 V,capacity 500 mA or higher (not included in the kit)
- PCB size: 1.45 x 0.79 inches
Circuit Operation
Daytime Operation
When sunlight strikes the solar panel connected to the PC point, the solar
panel provides a charging current to the battery through diode D1.
Simultaneously, the voltage generated by the solar panel is applied to the
base of TR1, switching the transistor to the ON state (saturation). When TR1
is active, it pulls the bias away from the subsequent stages, causing TR2 and
TR3 to enter the OFF state (cutoff). As a result.
Nighttime Operation
In the absence of illumination on the solar panel at terminal PC, the
voltage supply to the base of TR1 is removed, causing TR1 to stop
conducting (OFF state). This allows the biasing voltage to reach TR2 and
TR3, switching them to the ON state. Consequently, LED1 and LED2 are
automatically illuminated using the power stored in the battery.