We found this circuit in an old Mullard (Philips) documentation. The sensor consists of a reed-switch that is coupled to a magnet on one of the wheels of the vehicle.
This circuit uses an optical coupler called Raystor created by Raytheon in the 1960s. The circuit...
This filter, found in an old manual, has characteristics of reduced overvoltage given by the graph...
The purpose of this circuit is to provide a few watts of power to a heavy speaker with good sound...