Detailed explanation of the difference between thermal fuse and current fuse

In modern electronic equipment and electrical systems, fuses are important components for protecting circuit safety. They can cut off the current in time when an abnormality occurs in the circuit to prevent equipment damage or even cause a fire. Common fuse types are thermal fuses and current fuses. Although both are protective devices, there are significant differences in their working principles, application scenarios and performance characteristics. This article will analyze the differences between thermal fuses and current fuses in detail to help readers better understand and choose appropriate protection devices.

The thermal fuse (Thermal Fuse) is a temperature-sensitive protection element. When the ambient temperature exceeds its set threshold, the fuse material inside the fuse will melt, thus cutting off the circuit and preventing equipment damage due to overheating.

Current Fuse is a component that protects based on the size of the current. When the current flowing through the fuse exceeds its rating, the metal wire inside the fuse will melt due to overheating, cutting off the circuit and preventing current overload or short circuit.

The triggering of the thermal fuse is based on temperature and is mainly used to prevent equipment from malfunction or fire due to overheating; while the current fuse is based on current size and protects equipment from overcurrent or short circuit damage.

Therefore, thermal fuses are more suitable for monitoring the thermal status of equipment, while current fuses are suitable for current abnormality protection.

Thermal fuses are usually composed of heat-sensitive materials and fuse alloys, and their design pays more attention to sensitive response to temperature. Most of its packages are made of high-temperature resistant materials and can withstand a certain ambient temperature.

Current fuses are composed of thin metal wires. The diameter and material of the metal wire determine its rated current and fusing characteristics. The package is usually a glass or ceramic tube to ensure electrical insulation and mechanical strength.

Thermal fuses are widely used in household appliances (such as electric kettles, hair dryers, microwave ovens), battery packs and motors where temperature protection is required.

Current fuses are mainly used in various circuit boards, power systems, automotive electronics and other equipment that require overcurrent protection.

The thermal fuse responds slowly to temperature changes and requires the ambient temperature to reach the set value before it can be blown; while the current fuse responds quickly to overcurrent and can quickly cut off the circuit to prevent circuit damage.

Thermal fuses are generally disposable fuses and need to be replaced with new fuses after they are blown; current fuses are sometimes disposable, but some specially designed current fuses (such as resettable fuses) can automatically reset.

When selecting a thermal fuse, you need to set the appropriate fusing temperature based on the maximum operating temperature and safety temperature of the device.

When selecting a current fuse, you need to select the appropriate rated current and fusing characteristics based on the rated current of the circuit and the maximum possible short-circuit current.

Thermal fuses and current fuses are two different types of protection components, each serving different protection needs. The thermal fuse focuses on temperature abnormality protection and is suitable for preventing equipment from overheating; the current fuse focuses on current abnormality protection and prevents circuit overload and short circuit. Understanding their differences can help engineers and technicians choose the appropriate fuse according to specific application scenarios, thereby improving the safety and reliability of the equipment. Choosing the right fuse can not only ensure the normal operation of the equipment, but also effectively avoid safety accidents. It is an indispensable and important link in modern electronic and electrical design.