Found in an EDN from the 1980s, this circuit uses a double 555. The circuit activates a relay that controls a horn or siren. Next to the diagram we have the timings.
This circuit is from 1997 documentation, based on the well-known integrated circuit 555 and 4017....
This circuit is from 1980 documentation. We can exchange the BC177 for a BC557 and the TIP41 must...
From different input voltages V, it is possible to reduce the voltage to several fixed values...