What is the function of thermal fuse in circuit

Thermal links  also called thermal fuse  which is a temperature-sensing loop cut-off device. Thermal fuses can sense the overheating generated during the abnormal operation of electrical and electronic products, thereby cutting off the circuit to avoid the occurrence of fire. Commonly used in: hair dryer, electric iron, rice cooker, electric stove, transformer, electric motor, water dispenser, coffee pot, etc. The thermal fuse cannot be used again after operation, and only operates once at the fusing temperature.

A piece of fusible alloy wire is connected between the two pins of the thermal fuse. The fusible alloy wire is covered with special resin. The current can flow from one pin to another pin. When the temperature around the thermal fuse rises to its operating temperature , its fusible alloy melts and shrinks into a spherical shape and attaches to the ends of the two pins under the action of surface tension and the help of special resin. In this way, the circuit is permanently cut off, preventing further damage to the electrical appliance, and also preventing the resulting fire.