This circuit converts 12 V to 127Vac to power small electronics in the car. It was found in the 1993 edition of the Electronics Experimenter Handbook.
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....