Why can't a fuse resistor be used instead of a fuse? If the resistor is used for overload protection in the circuit, there are certain limitations. The reason is that when the current passing through the resistor exceeds the maximum withstand capability of the resistor, the resistor will be burned out, making the resistor open-circuit, so that the circuit will be too large when the circuit is overloaded. current burns. Therefore, although the resistor has an overload protection function similar to a fuse, it does not actually play a good protective role in circuit overload protection, so it is not safe to use a resistor instead of a fuse.
The fuse needs to have three basic functions in the circuit: protection function, load-carrying function and safety function.
The protection functions of fuses include overload protection and short-circuit protection. When the circuit in the circuit exceeds the maximum withstand value of the circuit, the fuse must act within the specified time range to block the current passing through the circuit and protect the circuit or components from being damaged. Overcurrent damage. If the fuse resistor is used instead of the fuse, the response time and action duration of the fuse resistor can be as accurate as the fuse, and the circuit cannot be protected in time. Although it can have some blocking effect on the overload current, when the overload current is too large, the circuit cannot be protected in time, which is much worse than the fuse. Therefore, the fuse resistor cannot be used instead of the fuse, otherwise the circuit and the circuit will be damaged when the circuit is overloaded or the circuit is damaged. part.
The load-carrying function of the fuse is guaranteed by the melting heat value, so that the fuse can withstand the pulse impact of a certain energy of the necessary switching times. We need to calculate and evaluate it when selecting, and the fuse itself does not have similar technical indicators. If it is too small, it will be interrupted by the pulse, and if it is used too much, it will have no protection function.
The safety function of the fuse is guaranteed by the rated voltage, breaking capacity and other indicators, especially through the authoritative third-party safety certification, but the fuse itself is not a safety component, and does not require safety certification, its safety can be imagined However, it is known that the protection function is insufficient in the first place, and it is difficult to ensure that there is no unsafe phenomenon that endangers the surrounding during the burning process.
From this, it can be concluded that although the fuse resistor has the action of overcurrent blowing, it cannot really play the same role as the fuse. The fuse resistor can be used in some circuits, which can reduce some costs, but if the overload protection components are installed in the circuit, the fuse resistor cannot be used instead of the fuse.
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