What should the secondary source for household alarms provide when in low battery condition?

The correct answer for what the secondary source for household alarms should provide when in a low battery condition is that it must produce audible and visible trouble signals. This requirement is crucial because it ensures that occupants are adequately informed about the status of the alarm system, especially during a low battery condition, which can jeopardize the reliable functioning of the fire alarm.

Audible signals, such as beeping or chirping sounds, serve to alert individuals in the vicinity that attention is needed, while visible indicators, such as flashing lights, can assist those who may have hearing impairments. The combination of both types of signals provides a comprehensive alert system, ensuring that everyone is notified regardless of their sensory abilities.

This is especially important for fire alarms where timely notifications can be life-saving, thus adherence to safety codes and standards generally requires such alerts during low battery situations. Such measures are in place to promote safety and ensure that alarms remain operational in the event of an emergency.