We find this circuit in an Electronic Design of the 90s. The used integrated circuit admits equivalents and next to the diagram are given the formulas for the calculation of the components used.
We found this circuit in an American publication from 1977. The circuit drives two LEDs according to...
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...
Similar circuits can be found on this site. This is from an 80's American documentation. The...