Found in a 1965 Electronic Design, this circuit produces a signal with the waveform shown in the figure from an input pulse. Components admit equivalents.
This circuit detects the presence of a pilot flame in heating systems by the presence of infrared...
In the figure we have a circuit that uses unusual components, being indicated for low frequency...
Found in older Signetics documentation, this circuit generates signals from 30 Hz to 25 kHz....