Found in documentation two years 80, this toy instrument uses an integrated circuit little commonly. As notes are given the values of key series resistors on the keyboard.
This circuit was found in the Raytheon transistors manual from the 1960s. The circuit uses...
This circuit was found in a 1970s RCA publication. Transistors support modern equivalent types....
This circuit for automotive use was found in American documentation from the 90s. The circuit uses...