Digital Electronics Logic Gates Questions and Answers

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Digital Electronics Logic Gates questions with answers form the base of circuit design and digital systems. Students preparing for GATE, DRDO, and BARC exams must understand AND, OR, NOT, NAND, NOR, XOR, and XNOR gate operations. Practicing these electronics MCQs improves problem-solving accuracy in truth tables, Boolean algebra, and logic circuit simplification. These programming-style questions with explanations are ideal for both technical interviews and competitive electronics exams.

Covers types and functions of logic gates. Complement with digital electronics combinational logic circuits and boolean algebra

Digital Electronics Logic Gates

Showing 10 of 78 questions

51. Which of the following is not a basic Boolean operation?

  • OR
  • NOT
  • AND
  • FOR
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52. Which of the following gates is described by the expression ?

  • OR
  • AND
  • NOR
  • NAND
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53. What is the Boolean expression for a four-input OR gate?

  • Y = A + B + C + D
  • Y = A· B · C · D
  • Y = A – B – C – D
  • Y = A $ B $ C $ D
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54. How many truth table entries are necessary for a four-input circuit?

  • 4
  • 8
  • 12
  • 16
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55. How many entries would a truth table for a four-input NAND gate have?

  • 2
  • 8
  • 16
  • 32
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56. The Boolean expression for a 3-input OR gate is ________.

  • X = A + B
  • X = A + B + C
  • X = ABC
  • X = A + BC
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57. From the truth table for a three-input NOR gate, what is the only condition of inputs A, B, and C that will make the output X high?

  • A = 1, B = 1, C = 1
  • A = 1, B = 0, C = 0
  • A = 0, B = 0, C = 1
  • A = 0, B = 0, C = 0
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58. The logic gate that will have a LOW output when any one of its inputs is HIGH is the:

  • NAND gate
  • AND gate
  • NOR gate
  • OR gate
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59. The output of a NAND gate is LOW if ________.

  • all inputs are LOW
  • all inputs are HIGH
  • any input is LOW
  • any input is HIGH
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60. A truth table illustrates how the input level of a gate responds to all the possible output level combinations.

  • TRUE
  • FALSE
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