Answer:
bimetallic thermoswitch that closed when heated to a high temperature
Explanation:
solution
operating principle of the spot detector sensor is bimetallic thermoswitch that closed when heated to a high temperature
A thermal switch system is one or more light energized power system and thermal switch that control operation of the light
and thermal switch is heat sensitive unit that is complete electrical circuit at some certain temperature
these are connected in parallel with each other
so here correct answer is bimetallic thermoswitch that closed when heated to a high temperature
