The integrated circuit used in this circuit from a 1987 documentation is no longer common today. This circuit can generate a multitude of different sounds and this circuit is an example of application.
This TTL circuit was found in the December 1990 issue of Radio Electronics magazine. The circuit has...
Found in an Electronics World of 1968 this circuit can use any SCR and diodes depending on the...
Placed near a telegraphic transmitter (CW) and with a small antenna or pickup, it reproduces the...