Which switch controls the external power in the system?

The battery switch is designated for controlling the external power within a system. Its primary function is to manage the flow of electricity from the battery to the various electrical components, either enabling or disabling their power supply. When the battery switch is turned on, it allows electrical systems to draw power from the battery or external sources, ensuring that the necessary components receive the energy they need for operation.

In contrast, the master switch typically regulates the entire electrical system, encompassing both battery and external power. The power switch might control individual electrical devices rather than the overall power supply to the system. The fuel switch is specific to the management of the fuel supply, unrelated to the electrical power systems. Hence, the battery switch is the most accurate choice for controlling external power in the system.