Found in American documentation from 1968, this circuit has an acute cut-off of the frequency to which it is tuned and which depends on RC. Transistors may be modern equivalents of general use.
We found this circuit in the June 1991 issue of Radio Electronics magazine. The circuit can be...
This precision circuit, which also functions as a bridge, was found in a February 1967 Popular...
We found this circuit in an old documentation from the 70s. The text is the original one of the...