This circuit was found in a 1969 US documentation. It provides a signal that can be externally programmed as suggested circuits. The circuit can be used as a shield.
Found in a 90's EDN this circuit can be used as a shield. The transistor is a general-purpose type and the...
This circuit was found in the November 1992 issue of Radio Electronics magazine. The circuit has...
This circuit was found in an American documentation from 1977. The circuit can be implemented with modern...