We found this circuit in an old American publication from the 1980s. Transistors can be general-purpose types like the BC548, and the tuning frequency is given by the L and C components.
Found in a publication by National Semiconductor, this circuit provides an output voltage of 3.3...
This shield can be used both to interface TTL circuits and microcontrollers. The resistor in...
This circuit was found in a Japanese documentation of the 70's. It uses transistors of the era and is...