Digital Electronics Questions with Solutions

40 questions24 easy16 medium

Digital electronics is the study of circuits that work with binary signals, and it forms the hardware basis of every computer. This topic covers logic gates (AND, OR, NOT, NAND, NOR, XOR and XNOR) and their truth tables, Boolean algebra and its laws, De Morgan's theorems, and simplifying Boolean expressions, including with Karnaugh maps (K-maps). It also covers combinational circuits such as half adders, full adders, multiplexers, demultiplexers, encoders and decoders, and sequential circuits such as flip-flops (SR, JK, D and T), registers and counters. Exam questions test writing or reading truth tables, simplifying expressions, and identifying the output of a given circuit. Remember that NAND and NOR are universal gates, which means any other gate can be built using only NAND gates or only NOR gates. Practise the digital electronics questions below, each with a step-by-step solution.

  1. Q1.

    Simplify the Boolean expression .

    A. B. C. D.
    easyAsked in MAH MCA CET 2025View solution ›
  2. Q2.

    A bulb in a staircase has two switches, one on the ground floor and the other on the first floor. The bulb can be turned ON and also turned OFF by either switch, irrespective of the state of the other switch. The logic of the switching of the bulb resembles

    A. an XOR gateB. an XNOR gateC. an AND gateD. an OR gate
    easyAsked in NIMCET 2023View solution ›
  3. Q3.

    The number of minterms in an -variable truth table is

    A. B. C. D.
    easyAsked in NIMCET 2023View solution ›
  4. Q4.

    Which circuit is used to store one bit of data?

    A. RegisterB. Flip FlopC. VectorD. Encoder
    easyAsked in TCS ExamView solution ›
  5. Q5.

    Which of the following can be called as universal gate?

    A. NOTB. NORC. ORD. AND
    easyAsked in TCS ExamView solution ›
  6. Q6.

    Chip is a common nickname for a(n)

    A. TransistorB. ResistorC. Integrated CircuitD. Semiconductor
    easyAsked in TCS ExamView solution ›
  7. Q7.

    Integrated Circuit (IC) chips used in computers are made with

    A. CopperB. AluminiumC. GoldD. Silicon
    easyAsked in TCS ExamView solution ›
  8. Q8.

    Let and be Boolean variables, where denotes OR and denotes AND. The simplified form of the Boolean expression is

    A. B. C. D.
    easyAsked in NIMCET 2011View solution ›
  9. Q9.

    Which one of the following is not a valid rule of Boolean algebra?

    A. B. C. D.
    easyAsked in NIMCET 2011View solution ›
  10. Q10.

    A switching circuit that produces one of a set of input bits as its output, based on the value of control bits, is termed a:

    A. Full adderB. InverterC. MultiplexerD. Converter
    easyAsked in NIMCET 2009View solution ›
  11. Q11.

    Assume x' represents negation of x. The Boolean function x'y' + xy + x'y is equivalent to?

    A. x' + yB. x + yC. x + y'D. x' + y'
    easyAsked in NIMCET 2020View solution ›
  12. Q12.

    The equivalence of given expression x + x'y with Boolean theorem is….

    A. xB. x + yC. x'D. 0
    easyAsked in NIMCET 2020View solution ›
  13. Q13.

    The Boolean expression is unaffected by the value of the Boolean variable

    A. AB. BC. CD. None of these
    easyAsked in NIMCET 2022View solution ›
  14. Q14.

    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):

    A. NORB. ANDC. ORD. NAND
    easyAsked in NIMCET 2022View solution ›
  15. Q15.

    The Boolean expression X(X + Y) is same as

    A. X . (1 + Y)B. XC. X . 1D. All of these
    easyAsked in NIMCET 2014View solution ›
  16. Q16.

    Which one of the following Boolean algebraic rules is correct?

    A. B. C. D.
    easyAsked in NIMCET 2017View solution ›
  17. Q17.

    Which of the following is a functionally complete set of gates?

    A. I but not IIB. II but not IC. Neither I nor IID. Both I and II
    easyAsked in NIMCET 2017View solution ›
  18. Q18.

    If a signal passing through a gate is initiated by sending a low into one of the inputs and the output is high, the gate is

    A. NORB. NANDC. ANDD. OR
    easyAsked in NIMCET 2018View solution ›
  19. Q19.

    If we can generate a maximum of 4 Boolean functions using n Boolean variables, what will be the minimum value of n?

    A. 65536B. 16C. 1D. 4
    easyAsked in NIMCET 2019View solution ›
  20. Q20.

    How many distinct Boolean functions can be formed with 3 Boolean variables?

    A. 16B. 1024C. 32D. 256
    easyAsked in NIMCET 2019View solution ›
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