Computer Knowledge
Digital Logic and Microprocessors
735 Questions
Digital logic and microprocessors form the core of computer science, covering logic gates, combinational and sequential circuits, and CPU architecture. These topics are crucial for computer knowledge sections in technical exams. Test your digital electronics basics here.
Logic gates and circuitsCombinational vs sequential circuitsMicroprocessor instructionsTruth tables and boolean functions
Digital Logic and Microprocessors Questions
B
Correct answer
Explanation
A full adder can be constructed using two half adders and one OR gate. The first half adder adds the two input bits, and the second adds the carry from the first to the third input bit.
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input
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output
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both (1) and (2)
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none of these
A
Correct answer
Explanation
In a half adder, the two bits being added are the augend and the addend. Both of these are input variables.
B
Correct answer
Explanation
A standard flip-flop has two outputs, typically denoted as Q and Q-bar (the complement of Q). These outputs are always in opposite states.
C
Correct answer
Explanation
A full adder is designed to add three bits: two significant bits and a carry-in bit from a previous stage. Thus, it has three inputs.
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normal
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complement
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both 1 and 2
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none of these
A
Correct answer
Explanation
In a flip-flop, Q is defined as the normal or primary output, while Q-bar is the complement output.
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half adder
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full adder
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flip-flop
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none of these
C
Correct answer
Explanation
Flip-flops are sequential circuits that provide complementary outputs (Q and Q-bar). Adders are combinational circuits that do not have complementary outputs.
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sum
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carry
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both 1 and 2
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none of these
B
Correct answer
Explanation
In a half adder, the carry output is generated by the AND operation of the two inputs, represented as xy.
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sum
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carry
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both 1 and 2
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none of these
A
Correct answer
Explanation
The expression x'y + xy' is the XOR operation, which represents the sum output of a half adder.
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Carry
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Divisor
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Multiplier
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None of these
A
Correct answer
Explanation
The two outputs of a half adder are the sum and the carry. Carry is explicitly listed as an option.
A
Correct answer
Explanation
A basic flip-flop is a bistable multivibrator capable of storing exactly one bit of binary information.
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storage
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control
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process
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none of these
A
Correct answer
Explanation
A flip-flop is a fundamental sequential logic circuit used as a basic storage element for binary data.
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addition of 2
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exponent of 2
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multiplication of 2
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subtraction of 2
C
Correct answer
Explanation
Shifting a binary number one bit to the left is equivalent to multiplying the number by 2. For example, 0011 (3) shifted left becomes 0110 (6).
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Arithmetic Logic Unit
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Control Unit
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Memory Unit
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Both (1) and (2)
A
Correct answer
Explanation
The Arithmetic Logic Unit (ALU) is the part of the CPU responsible for performing all mathematical calculations and logical comparisons.
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All inputs are 1
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Any one input is 0
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All inputs are 0
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None of these
B
Correct answer
Explanation
A NAND gate is the inverse of an AND gate. It outputs 0 only when all inputs are 1; otherwise, if any input is 0, the output is 1.
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OR and NOT
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Only NOR
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NAND and NOR
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Only NAND
C
Correct answer
Explanation
NAND and NOR gates are called universal gates because any other logic gate (AND, OR, NOT) can be constructed using only combinations of these gates.