A fuse is actually a type of short-circuit protector widely used in power distribution systems and control systems, mainly for short-circuit protection or severe overload protection. During operation, the fuse is connected in series in the protected circuit. When a short circuit or severe overload occurs in the circuit, the fuse element in the fuse will automatically melt, providing protection, and the most common one is the fuse. In addition, there is a circuit breaker, commonly known as an "air switch", which is also a type of short-circuit protector. When overcurrent occurs, it will automatically trip and provide protection; Fuses and circuit breakers are both protective electrical appliances. But they are not the same Circuit breakers are a general term, which can be divided into two types - frame circuit breakers and plastic shell circuit breakers. Frame type circuit breaker, commonly known as universal circuit breaker; Plastic shell circuit breakers are commonly known as air circuit breakers. They have short-circuit and overload protection and can be reused. The lifespan is generally between several thousand to tens of thousands of times. A fuse is an electrical device that protects the circuit by melting the fuse, and cannot be reused. After protection, it is necessary to replace the melt.

Their commonality is that they can both achieve short-circuit protection. The principle of a fuse is to use current flowing through a conductor to heat it up, and when the conductor reaches its melting point, it melts, thus disconnecting the circuit to protect electrical appliances and circuits from being burned out. It is an accumulation of heat, so it can also achieve overload protection. Once the melt burns out, it needs to be replaced. Circuit breakers can also achieve short-circuit and overload protection for power lines, but the principle is different. They use the current bottom magnetic effect (electromagnetic release) to achieve circuit breaker protection and the current thermal effect to achieve overload protection (not melting, no need to replace components in case of suspicion). In practice, when the electrical load in the circuit is close to the load of the fuse used for a long time, the fuse will gradually heat up until it melts. As mentioned in the above post, the melting of a fuse is the result of the combined action of current and time to protect the circuit, and it is a one-time action. And a circuit breaker is a device that automatically disconnects when the current in the circuit suddenly increases and exceeds the load of the circuit breaker. It is a protection for a momentary increase in current in the circuit, such as when there is a large leakage, short circuit, or momentary high current. When the cause is identified, it can be closed and continue to be used. As mentioned in the above post, the melting of a fuse is the result of the combined action of current and time, while a circuit breaker will trip as soon as the current exceeds its set value, and the effect of time can be almost ignored. Circuit breakers are commonly used components in low-voltage distribution nowadays. There are also some places where fuses are suitable, which will not be further discussed here.