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

1. The output of an AND gate with three inputs, A, B, and C, is HIGH when ________.

  • A = 1, B = 1, C = 0
  • A = 0, B = 0, C = 0
  • A = 1, B = 1, C = 1
  • A = 1, B = 0, C = 1
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2. If a 3-input NOR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?

  • 1
  • 2
  • 7
  • 8
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3. If a signal passing through a gate is inhibited by sending a LOW into one of the inputs, and the output is HIGH, the gate is a(n):

  • AND
  • NAND
  • NOR
  • OR
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4. A device used to display one or more digital signals so that they can be compared to expected timing diagrams for the signals is a:

  • DMM
  • spectrum analyzer
  • logic analyzer
  • frequency counter
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5. The output of an OR gate with three inputs, A, B, and C, is LOW when ________.

  • A = 0, B = 0, C = 0
  • A = 0, B = 0, C = 1
  • A = 0, B = 1, C = 1
  • all of the above
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6. Which of the following logical operations is represented by the + sign in Boolean algebra?

  • inversion
  • AND
  • OR
  • complementation
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7. Output will be a LOW for any case when one or more inputs are zero for a(n):

  • OR gate
  • NOT gate
  • AND gate
  • NOR gate
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8. How many pins does the 4049 IC have?

  • 14
  • 16
  • 18
  • 20
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9. Which of the following choices meets the minimum requirement needed to create specialized waveforms that are used in digital control and sequencing circuits?

  • basic gates, a clock oscillator, and a repetitive waveform generator
  • basic gates, a clock oscillator, and a Johnson shift counter
  • basic gates, a clock oscillator, and a DeMorgan pulse generator
  • basic gates, a clock oscillator, a repetitive waveform generator, and a Johnson shift counter
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10. TTL operates from a ________.

  • 9-volt supply
  • 3-volt supply
  • 12-volt supply
  • 5-volt supply
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