This circuit was found in the January 1991 issue of Radio Electronics magazine. The circuit uses integrated circuits of the time and the coils depend on the tuned bands.
This is the basic configuration of many LM339 manuals, as a comparator with hysteresis. The font...
We found this circuit in a Popular Electronics of the 80's. The circuit can be used to drive...
This simple power supply for transistors was found in documentation from the 1940s. The...