Question

How many OR gates are required for an octal-to-binary encoder?

(a) 3

(b) 2

(c) 8

(d) 10

I got this question in unit test.

I'm obligated to ask this question of Encoders in chapter Combinational Circuits of Digital Circuits

Answer 1

The correct option is (a) 3

To elaborate: An encoder is a combinational circuit encoding the information of 2^n input lines to n output lines, thus producing the binary equivalent of the input. Thus, in octal to binary encoder there are  8 (=2^3) inputs, thus 3 output lines.