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.
We found this relaxation oscillator in a 1967 General Electric documentation. The frequency is given...
This circuit is interleaved with the source of a portable AM or FM radio previously tuned to a...
This circuit produces a signal that has the waveform of the sound produced by or near the banjo....