OCFA Self-Contained Breathing Apparatus (SCBA) Practice Exam

The voice amplifier is a compact, wearable device that needs a light, low-voltage power source. It’s designed to run on three AAA batteries in series, which provides about 4.5 volts—enough to power the small amplifier and microphone while keeping the unit lightweight and compact for SCBA use. A 9-volt battery would be bulkier and ill-suited to the device’s current needs, and using larger cells like AA or C would add unnecessary weight and size. So, three AAA batteries is the intended power source.