This circuit for multiple sound inputs was found in a Radio Electronics from January 1992. It consists of a Bargraph connected to a multi-input mixer.
This source for devices for automotive use was found in a 1985 documentation. The power...
This circuit was found in a Japanese documentation of the 70's. It uses transistors of the era and is...
This circuit was found in a 1992 documentation but uses discrete components that can still be...