This QST circuit generates 4 frequency signals according to the crystals used. Transistors admit equivalents although the indicated types can still be found with some ease.
This JFET amplification stage was found in the April 1993 issue of Electronics Now. The input...
This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The...
Using a piezoelectric sensor of the time, this circuit was found in the February 1994 issue of...