Found in Radio Electronics from the 90s, this circuit is based on the 555 directly feeding a small tweeter. An amplifier stage can be added.
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...