Explore topic-wise MCQs in Digital Electronics.

This section includes 30 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 hexadecimal number (3E8)16 is equal to decimal number
A. 1000
B. 982
C. 768
D. 323
Answer» B. 982
Discussion
2.

The expression Y = pM (0, 1, 3, 4) is
A. POS
B. SOP
C. Hybrid
D. none of the above
Answer» B. SOP
Discussion
3.

Find the output voltage for 011100 in a 6 bit R-2R ladder D/A converter has a reference voltage of 6.5 V.
A. 6.4 V
B. 2.84 V
C. 0.1 V
D. 8 V
Answer» C. 0.1 V
Discussion
4.

Assertion (A): The output of a NOR gate is equal to the complement of OR of input variables.

Reason (R): A XOR gate is a universal gate.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
5.

Assertion (A): A demultiplexer can be used as a decoder.

Reason (R): A demultiplexer can be built by using AND gates only.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
6.

For a MOD-12 counter, the FF has a tpd = 60 ns The NAND gate has a tpd of 25 n sec. The clock frequency is
A. 3.774 MHz
B. > 3.774 MHz
C. < 3.774 MHz
D. 4.167 MHz
Answer» B. > 3.774 MHz
Discussion
7.

In a D latch
A. data bit D is fed to S input and D to R input
B. data bit D is fed to R input and D to S input
C. data bit D is fed to both R and S inputs
D. data bit D is not fed to any input
Answer» B. data bit D is fed to R input and D to S input
Discussion
8.

In a 7 segment display, LEDs b and c lit up. The decimal number displayed is
A. 9
B. 7
C. 3
D. 1
Answer» E.
Discussion
9.

If the inputs to a 3 bit binary adder are 1112 and 1112, the output will be 110.
A. True
B. False
Answer» C.
Discussion
10.

Assertion (A): TTL is a very popular logic in SSI and MSI category.

Reason (R): In Schottky TTL the power dissipation is less than in ordinary TTL.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
11.

Assertion (A): ECL gate has very high speed of operation.

Reason (R): Transistors in ECL do not go into saturation region.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
12.

Assertion (A): Tristate logic is used for bus oriented systems

Reason (R): The outputs of a tristate logic are 0, 1 and indeterminant.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
13.

Assertion (A): CMOS devices have very high speed.

Reason (R): CMOS devices have very small physical size and simple geometry.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» E.
Discussion
14.

Find the FSV (full scale voltage) in a 6 bit R-2R ladder D/A converter has a reference voltage of 6.5 V.
A. 6.4 V
B. 0.1 V
C. 7 V
D. 8 V
Answer» B. 0.1 V
Discussion
15.

Assertion (A): A multiplexer can be used for data routing.

Reason (R): A multiplexer has one input and many outputs.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
16.

Assertion (A): Synchronous counter has higher speed of operation than ripple counter

Reason (R): Synchronous counter uses high speed flip flops.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
17.

Assertion (A): ECL is fast as compared to TTL.

Reason (R): ECL dissipates less power than TTL.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» D. A is false, R is true
Discussion
18.

The applications of shift registers are

1.Time delay

2.Ring counter

3.Serial to parallel data conversion

4.Serial to serial data conversion

Which of the above are correct?
A. 1, 2, 3
B. 2, 3, 4
C. 1, 2, 3, 4
D. 1, 2, 4
Answer» D. 1, 2, 4
Discussion
19.

A 2 bit BCD D/A converter is a weighted resistor type with ER = 1V, R = 1 M and Rf = 10K then Resolution in percent and volt is __________ .
A. 1%, 1 mv
B. 10%, 10 mv
C. 10%, 1 mv
D. 1%, 10 mv
Answer» E.
Discussion
20.

Assertion (A): XOR gate is not universal gate.

Reason (R): It is not possible to realize any Boolean function using XOR gates only.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
21.

Assertion (A): In computers the data is stored in hexadecimal form

Reason (R): Hexadecimal representation is short as compared to binary representation.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» E.
Discussion
22.

In a 7 segment display the segments a, c, d, f, g are lit. The decimal number displayed will be
A. 9
B. 5
C. 4
D. 2
Answer» C. 4
Discussion
23.

The resolution of an n bit DAC with a maximum input of 5 V is 5 mV. The value of n is
A. 8
B. 9
C. 10
D. 11
Answer» D. 11
Discussion
24.

A 6 bit R-2R ladder D/A converter has a reference voltage of 6.5 V. It meets standard linearity then resolution in percent and volts.
A. 3% 7 V
B. 6.4 V, 2%
C. 0.1%, 1.57 V
D. 1.57%, 0.1 V
Answer» E.
Discussion
25.

What will be conversion rate for a counter type A/D converter contains a 4 bit binary ladder and a counter driven by a 2 MHz clock. Then conversion time
A. 125
B. 125 x 103
C. 125 x 106
D. None
Answer» E.
Discussion
26.

Which of the following characteristic are necessary for a sequential circuit?

1.It must have 6 gates

2.It must have feedback

3.Its output should depend on past value

Which of the above statements are correct?
A. 1, 2, 3
B. 1, 2
C. 2, 3
D. 1, 3
Answer» D. 1, 3
Discussion
27.

Assertion (A): Even if TTL gates and CMOS gates used in a realization have the same power supply of + 5 V, suitable circuit is needed to interconnect them

Reason (R): VOH, VOL, VIH and VIL of a TTL gave are respectively 2.4, 0.4, 2 and 0.8 V respectively. If supply voltage is + 5 V. VIL and VIH for CMOS gate for the supply voltage of + 5 V are 1.5 V and 3.5 V respectively.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
28.

In a 4 bit ripple counter using flip flops with tpd = 40 ns, the maximum frequency can be
A. 1.25 MHz
B. 3.25 MHz
C. 6.25 MHz
D. 12.5 MHz
Answer» D. 12.5 MHz
Discussion
29.

Assertion (A): A PROM can be used as a synchronous counter

Reason (R): Each memory location in a PROM can be read synchronously.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» E.
Discussion
30.

Assertion (A): The access time of memory is lowest in the case of DRAM

Reason (R): DRAM uses refreshing cycle.
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true
Answer» E.
Discussion