A thermal fuse is a safety device used to protect electrical circuits and equipment from overheating. It contains a temperature-sensitive element that melts or breaks the circuit when a specific temperature threshold is exceeded, thereby stopping the flow of electricity and preventing potential fire hazards or damage to sensitive components. Unlike circuit breakers or resettable fuses, a thermal fuse is a one-time-use device and must be replaced after it has been triggered. Thermal fuses are commonly found in household appliances, power supplies, and industrial equipment to enhance safety and prevent accidents caused by excessive heat.