Question

Which of the following combinations of logic gates can decode binary data 1101.

• A. one 4-input AND gate
• B. one 4- input AND gate, one inverter
• C. one 4-input AND gate, one OR gate
• D. one 4-input NAND gate, one inverter

Answer 1

The correct option is B one 4- input AND gate, one inverter

For decoding any binary data, output must be high for that data (code) and thus is possible in one 4-input AND gate, one inverter option only.
A decoder is a combinational circuit that converts $n-$ bit binary coded data upto $2^n$ outputs.