This circuit is from an 80's Electronic Engineering. The base is a common operating and 4 single integrated voltage comparators. The circuit directly drives 4 indicator LEDs.
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
This circuit was obtained from the 1976 Siemens integrated circuits manual. It is the circuit for...
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...