What do fire alarm signal devices contain?

Fire alarm signal devices primarily contain components designed to ensure effective operation and reliability in emergency situations. The correct choice, diodes, play a crucial role in these devices by allowing current to flow in one direction, which helps in managing the electrical signals within the system. Diodes can protect circuits from voltage spikes and ensure that the firing of alarms is precise and reliable, essential functions in a life safety system.

Battery backups, while integral to fire alarm systems for ensuring continued operation during a power outage, are not typically classified as part of the signal device itself. Battery backups provide the necessary power during such events but they do not directly form the signal-generating or alerting mechanism. Memory chips and transistors also have their applications in various electronic devices but are not specifically essential to the core functionality of fire alarm signal devices. The fundamental working principle relies heavily on diodes to ensure correct signaling during both normal and emergency situations.