What are the two primary functions of the regulator/rectifier unit in a motorcycle's electrical charging system?

1. It converts AC voltage from the stator to DC voltage to charge the battery, and regulates the DC voltage to a safe limit to prevent overcharging.
2. It increases the battery voltage from 12V to 24V for the headlights, and adjusts the ignition timing.
3. It stores electrical charge like a capacitor, and switches the starting motor solenoid on.
4. It filters engine oil debris and cooling system fluids electrically.