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.
In the figure we have a wireless wiretapping circuit for the frequency range determined by L1. For FM...
This voltage follower or amplifier with unit gain uses an unusual operational amplifier nowadays. The...
Found in a 90’s Electronics Now, this circuit has its output connected to an audio amplifier. The...