Digital Electronics

The radix of a number system represents

• number of repeated digits in that number system

• number of zeros in that number system

• number of digits in that number system

• number of non-zeros in that number system

The binary number 11011101 is equal to the decimal number

• 256

• 441

• 221

• 212

Which of the following logical operations is represented by the + sign in Boolean algebra?

• AND

• OR

• NOT

• Complementation

The output of a NOR gate is HIGH if ________.

• all inputs are HIGH

• any input is HIGH

• any input is LOW

• all inputs are LOW

Which of the examples below expresses the associative law of addition:

• A + (B + C) = (A + B) + C

• A + (B + C) = A + (BC).

• A(BC) = (AB) + C

• ABC = A + B + C

A certain logic gate with two inputs produces a low output only when both inputs are same; then it is

• an EX-OR gate

• an OR gate

• a NAND gate

• an AND gat

One of the following Boolean postulates is wrong:

• A + A = A

• A + A'= A

• A + A' = 1

• A * A' = 0

The CARRY expression for a half adder represents ______

• NAND gate

• XOR gate

• NOR Gate

• AND gate

The full adder can be realised using

• only two half adders

• two half adders and one ‘OR’ gate

• two half adders and one ‘AND’ gate

• only two ‘EX-OR’ gates

Which of the following are the universal logic gates

• AND and OR

• AND and NOT

• NAND and NOR

• XOR and XNOR