What do continuous-loop fire detection systems typically have embedded in their construction?

Continuous-loop fire detection systems are designed to monitor areas for temperature changes indicative of a fire. The correct answer is that these systems typically have a ceramic core embedded in their construction.

The ceramic core plays a crucial role in the operation of the continuous-loop systems. It is typically surrounded by a material that can expand and contract with temperature changes. When the temperature rises, it causes the core to change its physical state, which then can trigger an alarm. This design allows for constant monitoring along the length of the sensing element and ensures that any increase in temperature along the loop can be quickly detected, providing an effective means of fire detection in environments where conventional smoke or heat detectors may not be suitable.

The other options do not accurately represent what is found in continuous-loop systems. Optical sensors and thermal imaging units are more commonly associated with other types of fire detection systems that operate based on different principles, while electronic chips may be part of intelligent sensing systems, but they are not a defining characteristic specifically tied to continuous-loop technologies.