This circuit uses a parallel resonant crystal to control the frequency. The circuit is from Radio Electronics magazine, February 1993. Equivalent transistors can be used.
Found in a November 1977 Radio Electronics magazine, this digital circuit was described in an...
The TBA810 integrated circuit used in this 1982 project is not very common today, but if found it...
Found in an old Radio Electronics, this circuit uses common components today. The resistors of the IC...