QPlease tell me about the protective fuses used in testers.
The fuse is marked with the rated current.
Example labeling: 0.5 A/250 V. This 0.5 A is the rated current of the fuse. 250 V is the rated voltage.
The fuse will not blow up to this rated current value.
If the fuse continues to be used beyond this current value, the fuse may be damaged (fuse breakage, arcing, etc.) if the interrupting current value is exceeded, which may be dangerous.
Today, instead of conventional glass-tube fuses, there are fuses with enhanced safety features, such as arc-extinguishing material or ceramic-based fuses.