Voltage output of the alternator is controlled by regulating the?

The voltage output of an alternator is primarily controlled by regulating the field current. The field current is the electrical current supplied to the rotor of the alternator, which creates a magnetic field. The strength of this magnetic field directly influences the voltage produced by the alternator through electromagnetic induction.

By adjusting the field current, technicians can increase or decrease the strength of the magnetic field, thus varying the voltage output of the alternator to meet the demands of the electrical system in the vehicle. This regulation is crucial for maintaining the proper operation of electrical components and the battery charge.

The other options relate to the alternator's operation in different capacities. Output current refers to the actual electrical current supplied by the alternator, not directly controlling the voltage. Input voltage typically refers to voltage supplied to components, while load current pertains to the amount of current drawn by the electrical system. While these factors may interact with the alternator’s function, it is the field current that provides the mechanism for voltage regulation.