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.
The load controlled by this circuit depends on the triac used. The circuit is from Electronics Now magazine...
This circuit consists of a solid state doubler that doubles the supply voltage Ve between 5 and 15...
This circuit was found in an application note of the LTC1164 from Linear Technology of the 1990s....