We found this circuit in a 1977 factory documentation. The operational amplifiers can be 741 and the symmetrical power supply. Capacitors can be changed for operation at other frequencies.
This circuit was found in the February 1983 issue of Radio Electronics magazine. It is a 4-digit...
The circuit shown consists of a single switched power supply. We found it in English...
This logic level indicator was found in a 1988 documentation. The circuit can be used with both...