The fuse calculation formula can vary based on different circuit parameters and fuse specifications. The following are two common calculation formulas:

Select the rated current of the fuse based on the rated current of the circuit:

Fuse rated current = circuit rated current × coefficient

Among them, the coefficient is usually between 1.25 and 2, depending on the type and characteristics of the circuit. For example, for a circuit with a rated current of 10A, choosing a fuse with a rated current of 12.5A can ensure its normal operation and have the function of overload protection.

Calculate the rated current of the fuse based on the circuit short-circuit current and the fuse fusing time:

Fuse rated current = circuit short-circuit current × fuse time ÷ fuse current integration constant

Among them, the fuse time refers to the time that the fuse can cut off the current when the circuit is short-circuited, usually a few milliseconds; the fuse current integral constant is a parameter of the fuse, which reflects the accumulation and release characteristics of heat during the fuse process. , different models of fuses have different values.

The above are two common fuse calculation formulas, but in actual applications, calculations and selections need to be made according to specific circumstances. When selecting a fuse, you also need to consider factors such as the circuit's load characteristics, ambient temperature, and the capacity and characteristics of the fuse. It is recommended to seek help from professional electrical engineers in actual applications to ensure the safety and reliability of the circuit.