This circuit was found in documentation from the 1970s. However, it can be implemented with modern transistors such as 2N2222 for Q1 and BF494 for Q2. The crystal depends on the desired frequency.
This circuit, which appears at other times on this site has this version obtained in a Hands On of...
This circuit was obtained from an Auguist 1974 Everyday Electronics magazine. The circuit is still...
This circuit was found in an English publication from 1989. The integrated circuits are of the...