This circuit is a charger for single-cell lithium (Li-Ion) and Polymer (LiPo) batteries. It can sources energy from DC jack connectors (two different dimensions), USB-C and solar panel. It uses MCP73871 which has the peculiarity to smartly adjust the current sank, making it ideal for solar-powered applications, where the available energy could be really scarce and high-varying over time.
This schematic uses two LDRs (Light dependent resistor) to sense the light and a servo motor to automatically rotate the solar panel in the direction of the sun light. The Arduino code is available on [Arduino Solar Tracker using LDR and Servo Motor]