The main feature of this circuit found in an old American publication is that it is powered by the very signal it converts. The transistors are of the time and can be replaced by current types.
This circuit generates 50, 100 and 200 Hz signals from a 3.2768 MHz crystal and has outputs...
This circuit allows frequencies between 1.8 and 30 MHz to pass. Data for the coils is provided next to...
The automatic heating system sensor is a diode placed in a waterproof tube as shown in the figure....