Question

For 8-bit input encoder how many combinations are possible?

(a) 8

(b) 2^8

(c) 4

(d) 2^4

I got this question in examination.

The above asked question is from Encoders in portion Combinational Circuits of Digital Circuits

Answer 1

Correct answer is (b) 2^8

For explanation: 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. There are 2^8 combinations are possible for an 8-bit input encoder but out of which only 8 are used using 3 output lines. It is a disadvantage of encoder.