We found this simple toy organ circuit in the February 1968 issue of Radio Electronics magazine. The transistors were common at the time and the transformer was from a transistor radio output.
The circuit is from a June 1995 Electronics Now. The relay is power-dependent and both R1 and R2...
This circuit for several frequencies was obtained in an American documentation from the 90s. The...
The circuit shown in the figure is suggested by AllegroMicro (www.allegromicro.com) and consists of an...