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.
An stable multivibrator with 50% of duty cucle can be mounted using the 555 as shown by the...
This circuit was found in the old Mullard transistor reference manual from 1960. The circuit uses...
We found this circuit in a 1976 documentation. The transistor and the integrated circuit must have...