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 ouput push-pull stage using bipolar transistors was found in a publication of the year 1968....
This circuit is from an 80's documentation, applying to ordinary comparators. The source does not...
We find this circuit measuring from 1 to 1000 mW of power from small transmitters and oscillators in...