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.
The circuit in the figure is from a source with the possibility to adjust the output voltage from...
We found this circuit in a 1965 General Electric manual. The circuit applies to incandescent lamps only and...
We found this circuit in an American publication from 1977. The circuit drives two LEDs according to...