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 interesting low current circuit uses only one diode to obtain a full wave rectified signal....
The circuit shown is from a 1993 documentation. It uses two FETs in an oscillating configuration that...
This circuit serves to prevent devices powered by 6 V from being left with a power cut. The...