This circuit was found in the February 1993 issue of Radio Electronics magazine. Some components depend on the crystal frequency and can be changed.
This circuit was suggested by Motorola in a 1980s publication. It is based on a PUT that is not a...
Found in American documentation from the 70s, this circuit uses components of the time, uncommon...
This is an old circuit, but totally viable and with excellent sound quality. BD transistors must...