Computer Knowledge

Digital Logic and Microprocessors

749 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

Multiple choice

Consider the circuit shown below. The output of a 2:1 Mux is given by the function (ac' + bc).

Which of the following is true?

f = x1' + x2
f = x1'x2 + x1x2'
f = x1x2 + x1'x2'
f = x1 + x2

Reveal answer Fill a bubble to check yourself

Multiple choice

Consider the circuit given below the initial state Q₀ = 1,Q₁ = Q₂ = 0. The state of the circuit is given by the value 4Q₂+ 2Q₁+ Q₀

Which one of the following is the correct state sequence of the circuit?

1, 3, 4, 6, 7, 5, 2
1, 2, 5, 3, 7, 6, 4
1, 2, 7, 3, 5, 6, 4
1, 6, 5, 7, 2, 3, 5

Reveal answer Fill a bubble to check yourself

Multiple choice

Consider the following logic circuit whose inputs are functions f₁, f₂, f₃ and output is f

Given that f1(x,y, z) = $\sum$(0,1,3,5) f2(x,y,z) = $\sum$(6,7), and f (x,y,z) = $\sum$(1,4,5) f3 is

$\sum$ (1,4,5)
$\sum$ (6,7)
$\sum$ (0,1,3,5)
None of the above

Reveal answer Fill a bubble to check yourself

Multiple choice

Consider the following multiplexor where 10, 11, 12, 13 are four data input lines selected by two address line combinations A1A0 = 00,01,10,11 respectively and f is the output of the multiplexor. EN is the Enable input.

The function f (x,y,z) implemented by the above circuit is

xyz'
xy + z
x + y
None of the above

Reveal answer Fill a bubble to check yourself

Multiple choice

The finite state machine described by the following state diagram with A as starting state, where an arc label is $\dfrac{x}{y}$ and x stands for 1-bit input and y stands for 2-bit output.

Outputs the sum of the present and the previous bits of the input.
Outputs 01 whenever the input sequence contains 11
Outputs 00 whenever the input sequence contains 10
None of the above.

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Multiple choice

Minimum sum of product expression for f (w,x,y,z) shown in Karnaugh-map below is

xz + y'z
xz' + zx'
x'y + zx'
None of the above

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Multiple choice

Consider the following circuit with initial state Q₀ = Q₁ = 0. The D flip-flops are positive edged triggered and have set up times 20 nanosecond and hold times 0.

Consider the following timing diagrams of X and C ; the clock of C 40 nanosecond. Which one is the correct plot of Y

Reveal answer Fill a bubble to check yourself

Multiple choice

The Boolean function x'y' + xy + x'y is equivalent to

x' + y'
x + y
x + y'
x' + y

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Multiple choice

A circuit outputs a digit in the form of 4 bits. 0 is represented by 0000, 1 by 0001,...9 by 1001. A combinational circuit is to be designed which takes these 4 bits as input and outputs 1 if the digit $\ge$ 5, and 0 otherwise. If only AND, OR and NOT gates may be used, what is the minimum number of gates required?

Reveal answer Fill a bubble to check yourself

Multiple choice

A 4-bit carry look ahead adder, which adds two 4-bit numbers, is designed using AND, OR, NOT, NAND, NOR gates only. Assuming that all the inputs are available in both complemented and uncompensated forms and the delay of each gate is one time unit, what is the overall propagation delay of the adder? Assume that the carry network has been implemented using two-level AND-OR logic.