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 Wheatstone bridge has a thermistor or NTC sensor, allowing the measurement of temperatures by...
Relays from 20 mA to 200 mA can be driven by this sensitive circuit.6 or 12 V relays can be used...
This circuit is connected to the sum key of a common calculator. Adjusted to produce a pulse per...