8 bit comparator using IC 7485: A 8 bit comparator is a combinational circuit that compares two digital or binary numbers in order to find out whether one binary number is equal, less than or greater than the other binary number. Digital Comparators are made up from standard AND, NOR and NOT gates that compare the digital signals present at their input terminals and produce an output depending upon the condition of those inputs.

Fig:8 bit comparator using IC 7485:

An 8-bit comparator compares the two 8-bit numbers by cascading of two 4-bit comparators. The circuit connection of this comparator is shown above in which the lower order comparator A>B, A=B, and A

For the lower order comparator, the A=B cascade input must be connected High, while the other two cascading inputs A, B must be connected to LOW. The outputs of the higher-order comparator become the outputs of this eight-bit comparator.