This circuit is from 1967 General Electric documentation. It uses SUS which are not very common components today. The maximum frequency should not exceed a few kilohertz.
This circuit allows the use of headphones and microphones with diverse characteristics in audio...
We found this circuit in the 1994 Linear Applications Handbook from National Semiconductor. The...
This circuit was found in Radio Electronics from the 90s. The transistor is for general use. The...