What temperature-sensing device uses two dissimilar metals joined at the heated point?

What temperature-sensing device uses two dissimilar metals joined at the heated point?

• A. Riser
• B. Thermocouple
• C. Sprinkler
• D. Flow Hydrant

Answer: (B)

Two dissimilar metals joined at the sensing point form a thermocouple. When the junction where they meet is heated, a small electrical voltage is generated because of the Seebeck effect. The voltage produced is related to the temperature at that junction, and by measuring this voltage with the appropriate instrument, you can read the temperature. This is what a thermocouple does as a temperature-sensing device. The other terms listed—riser, sprinkler, and flow hydrant—are components or devices related to sprinkler systems, not temperature sensors.

Two dissimilar metals joined at the sensing point form a thermocouple. When the junction where they meet is heated, a small electrical voltage is generated because of the Seebeck effect. The voltage produced is related to the temperature at that junction, and by measuring this voltage with the appropriate instrument, you can read the temperature. This is what a thermocouple does as a temperature-sensing device. The other terms listed—riser, sprinkler, and flow hydrant—are components or devices related to sprinkler systems, not temperature sensors.