Digital Comparator explained
The principle of a Digital Comparator
A digital comparator, also called Magnitude comparator, is a combinational circuit circuit that compares two binary numbers to check which of the two numbers is smaller or larger or whether both numbers are equal.
These digital comparators are used in circuits for decision making; note that the outputs of these comparators are of the bool type.
The following video shows how a digital comparator works by comparing two 1-bit binary numbers.
4-bit magnitude comparator IC 7485
Digital Comparator symbol
The IC 7485 (TTL-series) as shown aside, is a 4-bit magnitude comparator . This IC compares the bits of the two numbers, starting with the most significant bit (MSB) and then with the least significant bit (LSB).
This IC 7485 is cascadable, i.e. binary numbers can also be compared beyond bit size 4. The following circuit shows the comparison of two 8-bit numbers by cascading two comparators 7485:
Digital Comparator 7485 - cascading two 4-bit comparators