# Electronics and Communication Engineering - Digital Electronics

46.

Assertion (A): XOR gate is not universal gate.

Reason (R): It is not possible to realize any Boolean function using XOR gates only.

Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is true, R is false
A is false, R is true
Explanation:

A universal gate is one which can be used to realize any Boolean function using that type of gates only. Only NOR and NAND are universal gates.

47.
The number of logic devices required in a Mod-16 synchronous counter are
4
5
6
7
Explanation:

4 flip-flops and 2 AND gates.

48.
A 2 bit BCD D/A converter is a weighted resistor type with ER = 1V, R = 1 MΩ and Rf = 10KΩ then Resolution in percent and volt is __________ .
1%, 1 mv
10%, 10 mv
10%, 1 mv
1%, 10 mv
Explanation:

Resolution % for BCD = where d is Resolution in volts.

Resolution in volts =

volts per step = 0.01V 0r 10mV.

49.
The number of bits in EBCDIC is
12
10
8
6