We found this test circuit in a March 1967 Radio Electronics. The circuit uses a zener-regulated supply and analog indicator.
Found in American documentation from the 1970s, this circuit can be designed based on a modern SCR,...
June 2017 - A wide variety of Rohm Semiconductor audio and codecs for audio is available from...
Found in a 1964 Electronic Design, this circuit must use transistors according to the supplied...