Question

How many inputs are required for a 1-of-10 BCD decoder?

(a) 4

(b) 8

(c) 10

(d) 2

The question was posed to me in an online interview.

Question is from Parity Generators/Checkers in section Combinational Circuits of Digital Circuits

Answer 1

Right answer is (a) 4

Explanation: A binary decoder is a combinational logic circuit which decodes binary information from n-inputs to a maximum of 2^n outputs. Therefore, for a BCD to decimal decoder, No. of inputs = 4 such that number of outputs is <= 2^n.