This organ, played by a probe was found in no old documentation, but it can be easily implemented these days. The integrated circuits are 555. The trimpot allows individual tuning of the keys.
Found in documentation from the 1980s, this circuit can generate signals in a range that reaches a few...
Found in a 1967 publication by General Electric, this control is intended for motors up to 2 A...
This circuit was found in a 90s Popular Electronics. The circuit uses components from that time,...