This circuit was obtained from Motorola documentation from 1969. The setting applies to other operating systems, including lower supply voltages. The zener determines the output signal.
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...