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 can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...
We found this circuit in a Hands-On Electroncs from the 90s. The circuit uses an LED indicator. Diodes...
We found this configuration in a documentation for radio amateurs from 1974. The circuit can be...