This circuit was found in the February 1985 issue of Radio Electronics magazine. It is based on an AY-3-1350 melody generator that was common at the time. It is suitable for analog lines only.
This circuit was obtained from an 80's documentation from General Electric. The circuit uses an...
The base of this circuit is one of the four Norton amplifiers existing in an LM3900 integrated circuit....
We found this circuit in an old publication. The components used are rare today. Accuracy depends on...