For 1990-2009 cars

The generator provides DC voltage to operate the vehicle's electrical systems and to recharge the battery. The voltage output of the generator is controlled by a built-in IC regulator. When the ignition switch is turned to the ON position, battery voltage is applied through the IG-COIL fuse (junction block), and the charge indicator to the IC regulator in the generator. When the generator is not rotating, the IC regulator provides a ground and causes the charge indicator to light. Voltage from the IG-COIL fuse ( junction block) also generates a magnetic field around the field coil. As the engine starts and the generator begins to rotate, a voltage is also generated in the stator. The IC regulator senses this voltage and takes control of the field current. AC voltage is generated in three stator coils. This AC voltage is converted to DC voltage in the rectifier bridge. The DC output, after being regulated by the IC regulator, is applied to the vehicle's battery and electrical supply circuits at the BAT terminal of the generator. A separate output voltage is provided to the charge indicator. Since equal voltage is now being provided to both sides of charge indicator, the lamp loses its ground and goes out. The IC regulator is also connected to battery voltage through the generator BAT terminal. When the battery is fully charged, the IC regulator decreases field excitation. This reduces the output of the generator to prevent overcharging. When the battery has been discharged or is heavily loaded, the IC regulator increases the field excitation and voltage output of the generator.