This circuit was found in a 1977 documentation. It limits the voltage from a source using zener diodes on the rectifier bridge. It is an unusual configuration today.
The circuit shown in the figure is suggested by ON Semiconductor (www.onsemi.com), based on its...
September 2016 - can be found at Mouser Electronics the new amplifiers with digital variable gain...
This simple 1-transistor audio preamplifier appeared in the June 1968 Radio Electronics magazine. The...