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 well-known siren configuration using complementary transistors is from a 1980s documentation. The...
This circuit was found in an old American magazine and could make use of more modern components...
This circuit is from the Philips integrated circuits manual of 1990. It is intended for magnetic...