What is a fuse and what is its function?

A fuse is the 1EC127 standard defines it as a "fuse-link". It is an electrical component installed in the circuit to ensure the safe operation of the circuit. The function of the fuse is: when the circuit fails or is abnormal, the current continues to rise, and the rising current may damage some important devices or valuable devices in the circuit, and may also burn the circuit or even cause a fire. If the fuse is correctly installed in the circuit, then the fuse will blow itself and cut off the current when the current abnormally rises to a certain height and temperature, thus protecting the safe operation of the circuit.

The earliest fuse was invented by Edison more than a hundred years ago. Because the industrial technology at that time was underdeveloped and incandescent lamps were very expensive, it was originally used to protect expensive incandescent lamps. How to understand the rated voltage of a fuse? Whether a fuse is blown or not depends on the amount of current flowing through it, regardless of the operating voltage of the circuit. The rated voltage of the fuse is proposed from the perspective of safe use of the fuse. It is the highest working voltage of the circuit where the fuse is in a safe working state. This means that the fuse can only be placed in circuits whose operating voltage is less than or equal to the rated voltage of the fuse. Only in this way can the fuse work safely and effectively, otherwise, when the fuse is blown, there will be continuous arcing and voltage breakdown, which will endanger the circuit.

How to explained the voltage drop of the fuse? The voltage drop of a fuse is the voltage drop across the fuse under the rated current condition. It reflects the internal resistance of the fuse and its value should not be too large. If a fuse with excessive internal resistance (voltage drop) is installed in the circuit, it will affect the system parameters of the circuit, causing the circuit to fail to work properly. The standard not only stipulates the upper limit of the value of voltage drop, but also stipulates its consistency.