This circuit is from an American documentation from the 90s. The transistors are of power and must be equipped with good heat sinks as well as the integrated voltage regulator.
Below are two frequency filters for receivers using crystals. The crystals must have the frequency of...
We found this circuit in a Radio Electronics from December 1963. The circuit combines valves and...
This circuit published in the November 1964 Radio Electronics magazine powers a light bulb but can...