This stereo meter-indicator was found in the August 1971 issue of Radio Electronics magazine. The transistors are known types and BC548 equivalents can be used.
This circuit was obtained in a Maxim documentation from the 90's. The circuit applies to...
Used in satellite TV receptions in the 1980s, this circuit was found in the March 1980 issue of...
We found this circuit in the April 2013 issue of Electronics Now. Any JFET can be used. Note the...