What device measures temperature by joining two dissimilar metals at the heated point?

What device measures temperature by joining two dissimilar metals at the heated point?

• A. Fusible Link
• B. Sprinkler
• C. Thermocouple
• D. OS&Y

Answer: (C)

The principle tested is a thermocouple. A thermocouple measures temperature by forming a junction between two dissimilar metals; when the junction is heated, a small voltage is generated due to the Seebeck effect, and this voltage varies with temperature. This allows temperature to be determined without an external power source and with a simple, rugged sensor often used in fire protection and related systems. In contrast, a fusible link is a safety device that melts at a specific temperature to release or isolate a component; it does not measure temperature. A sprinkler is a water-discharge device, not a sensor, and OS&Y refers to a type of valve mechanism, not a temperature-sensing element. Hence, the device described is a thermocouple.

The principle tested is a thermocouple. A thermocouple measures temperature by forming a junction between two dissimilar metals; when the junction is heated, a small voltage is generated due to the Seebeck effect, and this voltage varies with temperature. This allows temperature to be determined without an external power source and with a simple, rugged sensor often used in fire protection and related systems. In contrast, a fusible link is a safety device that melts at a specific temperature to release or isolate a component; it does not measure temperature. A sprinkler is a water-discharge device, not a sensor, and OS&Y refers to a type of valve mechanism, not a temperature-sensing element. Hence, the device described is a thermocouple.