This converter has coils according to the reception and converted frequency bands. We found it in the October 1989 Radio Electronics magazine in an article that teaches its construction.
The values of R and C are set so that a time constant of the same order of magnitude as the...
We found this circuit in an American documentation from 1975. The list of transistors that can be...
We found this configuration in a 1990 Poptronics. The circuit can be powered by voltages between 6 and...