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 has already been explored in other articles on this site. The high power is due to...
This circuit was found in a computer publication from the 1970s. The transistors can be the BD135...
This triac circuit was taken from an article in the July 1970 Radio Electronics magazine. Note the...