This circuit was found in documentation from the 1980s. The integrated circuit is from the time and the voltage depends on the desired power, and the component's datasheet should be consulted.
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...