The gain of this step is controlled by the feedback circuit depending on the strength of the input signal. The circuit will operate with modern general-purpose transistor.
Found in a 90s Popular Electronics, this circuit is interspersed between the filter and the...
This circuit is from an 80's documentation. The integrated circuit is from the time and the...
This circuit was found in a 80s American documentation. The zener diodes determine the points of...