What function does the concentrator serve in the OBOGs unit?

The concentrator in the On-Board Oxygen Generation System (OBOGS) plays a critical role by automatically adjusting the oxygen concentration based on the aircraft's current altitude. As altitude increases, the ambient air pressure decreases, which can lead to a drop in the partial pressure of oxygen. The concentrator is designed to ensure that the oxygen concentration delivered to the pilot remains at a safe and effective level, allowing for adequate breathing even at high altitudes. This automatic adjustment is vital for maintaining safe physiological conditions for the flight crew during various phases of flight.

In contrast, the other functions listed do not pertain to the primary role of the concentrator. For example, controlling the electrical power supply is typically managed by a different component of the aircraft's electrical systems. Providing a backup oxygen source involves separate equipment that ensures availability in case of primary system failure. Measuring cabin altitude relies on sensors that gauge the internal pressure, and while this information is essential for overall system safety and monitoring, it does not directly reflect the purpose of the concentrator.