We found this circuit in the October 1978 issue of Radio Electronics magazine. The magazine article describes its assembly. The circuit is a 6-digit circuit using components from the time.
This simple expandable circuit was obtained from a Popular Electronics from the 80's. The supply...
This traditional configuration found in a Radio Shack document can use 2N2646. More keys can be...
This circuit was obtained in an Argentine publication in 1976. It consists of a series voltage...