Found in a 90s Popular Electronics, this transistorized circuit generates pulses from 2 Hz to 50 kHz in three selectable ranges. The circuit has both AC and DC outputs.
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...