Question

3 bits full adder contains ________

(a) 3 combinational inputs

(b) 4 combinational inputs

(c) 6 combinational inputs

(d) 8 combinational inputs

I have been asked this question by my school teacher while I was bunking the class.

Asked question is from Combinational Circuits topic in section Combinational Circuits of Digital Circuits

Answer 1

Correct choice is (d) 8 combinational inputs

The explanation is: Full Adder is a combinational circuit with 3 input bits and 2 output bits CARRY and SUM. Three bits full adder requires 2^3 = 8 combinational circuits.