Question

A logic circuit that provides a HIGH output for both inputs HIGH or both inputs LOW is __________

(a) Ex-NOR gate

(b) OR gate

(c) Ex-OR gate

(d) NAND gate

I got this question during an interview.

My question comes from Controlled Inverter topic in chapter Arithmetic Circuits of Digital Circuits

Answer 1

Correct choice is (a) Ex-NOR gate

Easiest explanation: EX-OR gate gives 1 if both inputs are different means 0 or 1 and gives 0 if both are same and EX-NOR is opposite of EX-OR gate, so it provides a HIGH output for both inputs HIGH or both inputs are LOW. Thus, EX-NOR produces output for even number of 1’s or all 0s, while EXOR produces output for odd number of 1’s.