This circuit was found in a RE Experimenter Handbook from the 90's. The components are of the time, rare nowadays, except the 555 and 4017.
This receiver for infrared remote control was found in the Philips Databook of 1990, The circuit...
Found in an English publication from the 1980s, this circuit uses components that are still common...
This circuit was found in Maxim's documentation from the 90's. The frequency of the circuit is...