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
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Arithmetic operators
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Relational operators
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Bitwise operators
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None of these
C
Correct answer
Explanation
These operators are used to perform operations at Bit-level as all data is stored in the computer's memory as a sequence of bits (0's and 1's) .
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(b) has numeric co-processor but (a) does not have it.
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(a) contains catch controller but (b) does not have it.
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(a) has numeric co-processor but (b) does not have it.
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(b) has catch controller but (a) does not have it.
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None of these
A
Correct answer
Explanation
486 DX included a built-in math co-processor, which is also called numeric co-processor but 486 SX does not have such co-processor.
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Parity bits are used as the simplest form of error detecting code.
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There are two variants of parity bits.
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Odd parity is a special case of a cyclic redundancy check (CRC).
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Parity is used in many hardware applications.
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Parity data is used by some RAID levels to achieve redundancy.
C
Correct answer
Explanation
Even parity is a special case of a cyclic redundancy check (CRC), where the 1-bit CRC is generated by the polynomial x+1.
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FULL adder
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NAND gate
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Exclusive - OR gate
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None of these
C
Correct answer
Explanation
EX - OR gate behaves like an odd parity checker. The Ex- OR gate asserts its output when the input stream contains an odd number of 1's .
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Octal to binary converter
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Encoder
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Processor
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Multiplexer
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Binary adder
A
Correct answer
Explanation
Octal to binary converter is used to convert octal code to binary code.
C
Correct answer
Explanation
NOT gate complements the given input. Hence, it works as an inverter.
E
Correct answer
Explanation
An AND gate gives output high, when all its inputs are high. A NAND gate negates the output of AND gate. Hence the output is low, when all the inputs are high.
D
Correct answer
Explanation
A NOT gate can be implemented using a NAND gate by connecting both the inputs of the NAND gate together.A NAND Gate performs the AND-NOT function.Removing the NOT gate at the outputof the NAND gate results in an AND gate. The effect of the NOT gate at the output of the NAND gate can be cancelled by connecting a NOT gate at the output of the NAND Gate.An OR Gate can be implemented using a combination of three NAND gates. The implementation is based on the alternate symbolic representation of the OR gate.
B
Correct answer
Explanation
The AND gate performs a logical multiplication function.
The multiplication function performed by the AND gate is shown in the function table for a two input AND gate.
The expression describing the operation of a two inputs AND gate is F = A.B
The '.' is an AND operator and the expression represents an AND operation between inputs A and B.
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Instruction registers
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Data register
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Action registers
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Program counter
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Accumulator
E
Correct answer
Explanation
An accumulator is a register in which intermediate arithmetic and logic results are stored.
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i<<1
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i>>1
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i<<2
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i>>2
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none of these
A
Correct answer
Explanation
It shifts the bits of the number towards left by 1 bit. Hence it is equal to multiplying the whole number by 2.
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A full adder has a combinational circuit of three input and two output.
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A half adder has two input and two output combinational circuits.
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XOR gate can be used in half adder, full adder and subtractor.
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Only (1) and (2).
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(1), (2) and (3) all are true.
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OR Gate
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XOR Gate
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NAND Gate
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NOR Gate
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None of the above
A
Correct answer
Explanation
This is not a derived gate, it is a basic gate.
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Program counter
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Accumulator
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Instruction register
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None of these
B
Correct answer
Explanation
Accumulator register is designated to hold the result of an operation performed by the ALU.
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Direct addressing mode
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Intrasegment Direct Addressing Mode
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Register addressing mode
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Instruction
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Operand
B
Correct answer
Explanation
The effective branch address is the sum of an 8 or 16 bit displacement and the current contents of IP in 8086 processor.