Explore topic-wise MCQs in Digital Electronics.

This section includes 223 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Electronics knowledge and support exam preparation. Choose a topic below to get started.

1.

The Boolean expression is equal to ________.

A. C
B. D
C. C + D
D. 1
Answer» D. 1
Discussion
2.

The binary value of 1010 is converted to the product term .

A. True
B. False
Answer» C.
Discussion
3.

In Boolean algebra, = A.

A. True
B. False
Answer» B. False
Discussion
4.

For the SOP expression , how many 1s are in the truth table's output column?

A. 1
B. 2
C. 3
D. 5
Answer» D. 5
Discussion
5.

The Boolean expression is logically equivalent to what single gate?

A. NAND
B. NOR
C. AND
D. OR
Answer» B. NOR
Discussion
6.

When are the inputs to a NAND gate, according to De Morgan's theorem, the output expression could be:

A. =
B. +
C. = (
D. )(
E. )
Answer» B. +
Discussion
7.

Which Boolean algebra property allows us to group operands in an expression in any order without affecting the results of the operation [for example, + = + ]?

A. associative
B. commutative
C. Boolean
D. distributive
Answer» C. Boolean
Discussion
8.

The truth table for the SOP expression has how many input combinations?

A. 1
B. 2
C. 4
D. 8
Answer» E.
Discussion
9.

For the SOP expression , how many 0s are in the truth table's output column?

A. zero
B. 1
C. 4
D. 5
Answer» D. 5
Discussion
10.

A truth table for the SOP expression has how many input combinations?

A. 1
B. 2
C. 4
D. 8
Answer» E.
Discussion
11.

Determine the values of A, B, C, and D that make the product term equal to 1.

A. A = 0, B = 1, C = 0, D = 1
B. A = 0, B = 0, C = 0, D = 1
C. A = 1, B = 1, C = 1, D = 1
D. A = 0, B = 0, C = 1, D = 0
Answer» B. A = 0, B = 0, C = 0, D = 1
Discussion
12.

One of De Morgan's theorems states that . Simply stated, this means that logically there is no difference between:

A. a NOR and an AND gate with inverted inputs
B. a NAND and an OR gate with inverted inputs
C. an AND and a NOR gate with inverted inputs
D. a NOR and a NAND gate with inverted inputs
Answer» B. a NAND and an OR gate with inverted inputs
Discussion
13.

The commutative law of Boolean addition states that + = × .

A. True
B. False
Answer» C.
Discussion
14.

Determine the values of A, B, C, and D that make the sum term equal to zero.

A. A = 1, B = 0, C = 0, D = 0
B. A = 1, B = 0, C = 1, D = 0
C. A = 0, B = 1, C = 0, D = 0
D. A = 1, B = 0, C = 1, D = 1
Answer» C. A = 0, B = 1, C = 0, D = 0
Discussion
15.

Which output expression might indicate a product-of-sums circuit construction?

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
16.

The commutative law of Boolean addition states that A + B = A × B.

A. True
B. False
Answer» C.
Discussion
17.

Identify the Boolean expression that is in standard POS form.

A. [A].
B. [B].
C. [C].
D. (A + B)(C + D)
Answer» D. (A + B)(C + D)
Discussion
18.

The Boolean expression can be reduced to ________.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
19.

The standard SOP form of the expression is ________.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
20.

The Boolean expression for the logic circuit shown is _____.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
21.

Applying DeMorgan's theorem and Boolean algebra to the expression results in ________.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
22.

Which is the correct logic function for this PAL diagram?

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
23.

From the truth table below, determine the standard SOP expression.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
24.

Convert the following SOP expression to an equivalent POS expression.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
25.

Derive the Boolean expression for the logic circuit shown below:

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
26.

Applying DeMorgan's theorem to the expression , we get ________

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
Discussion
27.

Applying the distributive law to the expression , we get ________.

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
28.

In Boolean algebra, the term sum of products means

A. the AND function of several OR functions
B. the OR function of several AND functions
C. the OR function of several OR functions
D. the AND function of several AND functions
Answer» C. the OR function of several OR functions
Discussion
29.

Direction: The following item consists of two statements, one labelled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below:Statement (I): XOR gate is not a universal gateStatement (II): It is not possible to realize all Boolean functions using XOR gates only

A. Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I
B. Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I
C. Statement I is true but Statement II is false
D. Statement I is false but Statement II is true
Answer» B. Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I
Discussion
30.

A Boolean function F of three variables X, Y, and Z is given asF (X, Y, Z) = (Xʹ + Y + Z)˖(X + Yʹ + Zʹ )˖(Xʹ + Y + Zʹ )˖( Xʹ Yʹ Zʹ + Xʹ Y Zʹ + X Y Zʹ )Which one of the following is true

A. F (X, Y, Z) = (X + Y + Zʹ)˖( Xʹ + Yʹ +Zʹ
B. F (X, Y, Z) = (Xʹ + Y)˖(X + Y ʹ+ Zʹ )
C. F (X, Y, Z) = Xʹ Zʹ + Y Zʹ
D. F (X, Y, Z) = Xʹ Yʹ Z + X Y Z
Answer» D. F (X, Y, Z) = Xʹ Yʹ Z + X Y Z
Discussion
31.

In the circuit shown, A and B are the inputs and F is the output. What is the functionality of the circuit?

A. Latch
B. XNOR
C. SRAM Cell
D. XOR
Answer» C. SRAM Cell
Discussion
32.

A problem detector system produces an alarm in the factory when one of the three conditions occurs. The system is designed as such tha only one condition can occur at a time. If the three conditions are defined as q, r, and s respectively, the output logic for the system is given as

A. q̅rs + r̅ s̅
B. qr̅ s̅ + q̅sr̅ + q̅rs̅
C. qrs̅ + r̅
D. q + r + s
Answer» C. qrs̅ + r̅
Discussion
33.

A tristate logic device is a

A. Special logic device which has three states "High" "LOW" & Low Impedance
B. Special logic device which has three states "High" "LOW" & "Always High"
C. Quantization Special logic device which has three states "High" "LOW" & High Impedance
D. Precision Special logic device which has three states "High" "LOW" & "Always High"
Answer» D. Precision Special logic device which has three states "High" "LOW" & "Always High"
Discussion
34.

AB + AB' =

A. B
B. A
C. 1
D. 0
Answer» C. 1
Discussion
35.

AND-OR realization is equivalent to

A. OR-AND
B. NAND–NAND
C. NOR – NOR
D. None of the above
Answer» C. NOR – NOR
Discussion
36.

Calculate the dual of the Boolean expression (B’ + C) . A.

A. (B' . A) + C
B. (B' . C) + A
C. (B' . A) + A
D. (B' . C') + A
Answer» C. (B' . A) + A
Discussion
37.

In the below circuit, X =?

A. A + B
B. A
C. A.B
D. B
Answer» D. B
Discussion
38.

Direction: The following item consists of two statements, one labelled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below:Statement (I): When all inputs of a NAND gate are shorted to get a single input, single output gate, it becomes an inverter.Statement (II): When all inputs of a NAND gate are at logic ‘0’ level, the output is at logic ‘0’ level.

A. Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I
B. Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I
C. Statement I is true but Statement II is false
D. Statement I is false but Statement II is true
Answer» D. Statement I is false but Statement II is true
Discussion
39.

Identify the function of logic circuit given below

A. XNOR
B. AND
C. OR
D. XOR
Answer» E.
Discussion
40.

_______ is a graphical representation that provides a systematic method for simplifying the Boolean expressions.

A. B-tree
B. Logic Gate
C. Truth Table
D. K-map
Answer» C. Truth Table
Discussion
41.

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

A. an AND gate
B. an OR gate
C. an XOR gate
D. a NAND gate
Answer» D. a NAND gate
Discussion
42.

A circuit that is working as a NAND gate with a positive level logic system will work as _______ gate with a negative level logic system.

A. NAND
B. NOR
C. AND
D. OR
Answer» C. AND
Discussion
43.

A Karnaugh map (K-map) with 4 variables has _________ cells.

A. 2
B. 8
C. 16
D. 32
Answer» D. 32
Discussion
44.

For a 3-input logic circuit shown below, the output Z can be expressed as

A. Q + R̅
B. PQ̅ + R
C. Q̅ + R
D. P + Q̅ + R
Answer» D. P + Q̅ + R
Discussion
45.

Digital circuit can be made using only _____ gates

A. AND
B. NOT
C. OR
D. NOR
Answer» E.
Discussion
46.

Logic function AB̅D + AB̅D̅ can be reduced to

A. A̅ B̅
B. A B̅
C. B̅ D̅
D. A D̅
Answer» C. B̅ D̅
Discussion
47.

Booth algorithm is associated with

A. Binary division
B. Binary integer multiplication
C. Sorting binary integers
D. Searching of binary data
Answer» C. Sorting binary integers
Discussion
48.

If the Boolean expression P̅Q + QR + PR is minimized, the expression becomes:

A. P̅Q + QR
B. P̅Q + PR
C. QR + PR
D. P̅Q + QR + PR
Answer» C. QR + PR
Discussion
49.

Considering X as a binary variable, the Boolean expression X.X’ is equivalent to

A. X
B. 1
C. 0
D. X’
Answer» D. X’
Discussion
50.

In the logic circuit shown below, the output F = _____

A. 0
B. 1
C. X
D. X'
Answer» B. 1
Discussion