This circuit was obtained in a Popular Electronics of the 90s. The circuit uses integrated from the time, uncommon today. Note that the speaker has a higher impedance than ordinary speakers.
This circuit fires by burning the fuse when the input voltage exceeds the value referenced by the zener....
The UAA180 integrated circuit is no longer manufactured, but if the reader finds one in a scrap...
We find this circuit in a Radio Electronics of July 1984. It consists of the traditional version of 1 A...