We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit (double 555). The relay must be 12 V with contacts that support the horn current.
This interesting circuit of a 1988 documentation consists of a mouse trap where the sensor is left to...
Using an operational amplifier, this circuit was found in the March 1996 issue of Electronics Now...
Found in a 1980s documentation, this circuit makes use of components from that time. Modern...