I got this circuit from a 1977 English magazine. It can still be easily assembled, as the components are common. What this circuit does is to force the fuse to blow when the input voltage exceeds the zener diode voltage. The transistor can be any type of power that can withstand the fuse burning current. TIP31 to 2 A, for example. The input voltage can typically be 6 to 25 V. Since the conduction and burning of the fuse is very fast, there is no need to use a heatsink on the transistor.
