We found this circuit in documentation from the 1980s. The transformer is of the low voltage type with a 1: 3 turn ratio and the transistors can be of general-purpose types.
We found this circuit with JFETs in a Radio Electronics magazine from June 1969. The circuit has...
This detector with ultra-low deviation was found in an American documentation from the 90s....
This circuit is connected to the input of a good amplifier serving as a follower of audio signals or...