circuit diagram

 Solar energy

This circuit diagram illustrates a simple solar battery charging regulator using NPN transistors (S8050 and BC548) and a 6.2V Zener diode for voltage regulation. The solar panel provides power to charge the 6V battery, while the circuit ensures proper voltage regulation and prevents overcharging. 

The Zener diode acts as a voltage limiter, allowing current to pass only when the battery voltage drops below the threshold. The BC548 transistor works as a control switch, regulating the operation of the S8050 transistor, which handles the main current flow to the battery. Resistors (3.3kΩ and 1kΩ) help in proper biasing of the transistors, ensuring smooth switching operation.

 When the battery reaches full charge, the circuit automatically stops the charging process, preventing overvoltage damage.

 This simple yet effective design makes it suitable for small-scale solar power applications like emergency lighting and portable energy storage.