Final answer:
A fusible link-type heat detector uses a metal with a low melting point to break an electrical connection when it detects high temperatures, serving as a fire detection mechanism. Unlike a fuse that responds to high current, the fusible link is triggered by high temperatures, melting to interrupt the circuit and signal a potential fire.
Step-by-step explanation:
A fusible link-type heat detector is a safety device used in various applications, including fire detection systems. It contains a piece of metal or a wire that is designed to melt when the temperature reaches a certain level, indicating an excessive rise that could be indicative of a fire. These detectors act as part of an electric circuit where the fusible link ensures an interrupt in the electrical connection when the ambient temperature exceeds the designed threshold, thus triggering an alarm or other safety response.
A fusible link typically includes a metal with a low melting point. This metal is placed under tension between two electrical contacts. When exposed to high temperature, as a result of a fire for instance, the heat causes the kinetic energy of the charged particles within the conductor to increase, consequently converting into thermal energy. This heat will cause the fusible metal to melt, breaking the connection and thereby stopping the electrical flow. This disconnection acts as a signal, usually leading to the activation of the fire alarm system.
Similarly, the function of a fuse in an electrical circuit is to provide overcurrent protection. The wire in a fuse also has a low melting point and is designed to melt when a current exceeding the rated value passes through, thereby providing protection by breaking the circuit. However, unlike a fusible link in a heat detector, which is specifically designed to respond to high temperatures, fuses respond to high current irrespective of the ambient temperature.