Digital Electronics Questions with Solutions
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.
- Q21.
The minimum number of NAND gates required for implementing the Boolean expression is
A. 1B. 0C. 2D. 3mediumAsked in NIMCET 2022View solution › - Q22.
Which of the following is equivalent to the Boolean expression ?
A. B. C. D.mediumAsked in NIMCET 2022View solution › - Q23.
Write the simplified form of the Boolean expression .
A. B. C. D.mediumAsked in NIMCET 2022View solution › - Q24.
The Boolean expression is unaffected by the value of the Boolean variable
A. AB. BC. CD. None of theseeasyAsked in NIMCET 2022View solution › - Q25.
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. NANDeasyAsked in NIMCET 2022View solution › - Q26.
The Boolean expression X(X + Y) is same as
A. X . (1 + Y)B. XC. X . 1D. All of theseeasyAsked in NIMCET 2014View solution › - Q27.
Which one of the following Boolean algebraic rules is correct?
A. B. C. D.easyAsked in NIMCET 2017View solution › - Q28.
Which term is redundant in the expression AB + A'C + BC?
A. BCB. A'CC. ABD. None of thesemediumAsked in NIMCET 2017View solution › - Q29.
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 IIeasyAsked in NIMCET 2017View solution › - Q30.
The total number of binary functions that can be defined using n Boolean variables is
A. B. C. D. None of thesemediumAsked in NIMCET 2017View solution › - Q31.
Which one of the following expressions does NOT represent the exclusive NOR of x and y?
A. B. C. D.mediumAsked in NIMCET 2018View solution › - Q32.
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. OReasyAsked in NIMCET 2018View solution › - Q33.
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. 4easyAsked in NIMCET 2019View solution › - Q34.
How many distinct Boolean functions can be formed with 3 Boolean variables?
A. 16B. 1024C. 32D. 256easyAsked in NIMCET 2019View solution › - Q35.
Any given truth table can be represented by
A. a Karnaugh mapB. a product of sums Boolean expressionC. a sum of products Boolean expressionD. all of the optionseasyAsked in NIMCET 2024View solution › - Q36.
The expression P + QR is the reduced form of ______
A. (P + R)QB. (P + Q)(P + R)C. PQ + QRD. (P + Q)ReasyAsked in NIMCET 2024View solution › - Q37.
The Boolean expression for the following truth table is ______ x y z f 0 0 0 0 0 0 1 0 0 1 0 1 0 1 1 0 1 0 0 0 1 0 1 1 1 1 0 0 1 1 1 1
A. F = x'yz' + xy'z + x'y'z'B. F = x'y'z' + xy'z + xyz'C. F = x'yz' + xy'z + xyzD. None of thesemediumAsked in NIMCET 2024View solution › - Q38.
Which of the following is the CORRECT truth table for the XOR gate with two binary inputs A and B? (Outputs are listed for AB = 00, 01, 10, 11 in that order.)
A. 1, 0, 0, 1B. 0, 1, 1, 0C. 0, 0, 1, 1D. 1, 1, 1, 0easyAsked in NIMCET 2025View solution › - Q39.
Consider the Boolean function in a CPU control unit: Which of the following is equivalent to Y?
A. B. C. D.mediumAsked in NIMCET 2025View solution › - Q40.
Given the Boolean expression , which of the following rows in the truth table would have an output of 1 (True)?
A. A = 0, B = 0, C = 0B. A = 0, B = 1, C = 0C. A = 1, B = 1, C = 1D. A = 1, B = 0, C = 1easyAsked in NIMCET 2025View solution ›