Digital Electronics — Part 2 MCQs with Explanations

a-2, b-1, c-3 is the correct answer to “Match List-I with List-II and select the correct answer using the options given below the lists: List-I (Memory elements) List-II (Properties) a. Semiconductor 1. Destructive memory read out b. Ferrite core memory 2. Combinational logic c. Magnetic tape memory 3. Non-volatile”. This question is standard in competitive examination syllabi for Digital Electronics.

Synchronous counter is the correct answer to “The highest speed counter is”. This question is standard in competitive examination syllabi for Digital Electronics.

$$\left( {\overline {{\text{A}} + {\text{B}}} + {\text{C}}} \right)\left( {\overline {\text{D}} \overline {\text{E}} } \right)$$ is the correct answer to “The circuit shown in figure realizes the function:”. This question is standard in competitive examination syllabi for Digital Electronics.

11101101 is the correct answer to “Given the decimal number -19, and eight bit two's complement representation is given by”. This question is standard in competitive examination syllabi for Digital Electronics.

one data input and 256 data outputs is the correct answer to “A DEMUX with an 8-bit select input has:”. This question is standard in competitive examination syllabi for Digital Electronics.

a NAND or NOR is the correct answer to “If the output of a logic gate is '1' when all its inputs are at logic '0', the gate is either”. This question is standard in competitive examination syllabi for Digital Electronics.

None of the above is the correct answer to “Which of the following flip-flop cannot be converted to D-type (delay) flip-flop”. This question is standard in competitive examination syllabi for Digital Electronics.

Half-flash A/D converter is the correct answer to “Among the following types of A/D converters, name the one which the analog signal is sampled at a frequency much higher than the Nyquist rate”. This question is standard in competitive examination syllabi for Digital Electronics.

31 is the correct answer to “The number of comparators carried out in a 5 bit flash type A/D converter is”. This question is standard in competitive examination syllabi for Digital Electronics.

A is the correct answer to “In the expression A(A + B) by writing the first term A as (A + 0), the expression is best simplified as”. This question is standard in competitive examination syllabi for Digital Electronics.

2 NMOS transistors is the correct answer to “In a 3-input CMOS NAND gate, the substrate terminals of NMOS transistors are grounded (lowest potential available in the circuit) and the substrate terminals of PMOS transistors are connected to V DD (maximum positive potential in the circuit). Which of the following transistors may suffer in this circuit from body bias effect”. This question is standard in competitive examination syllabi for Digital Electronics.

00 → 01 → 11 → 10 → 00 . . . . is the correct answer to “A 2-bit synchronous counter using two J-K flip flops is shown. The expressions for the inputs to the J-K flip flops are also shown in the figure. The output sequence of the counter starting from Q 1 Q 2 = 00 is”. This question is standard in competitive examination syllabi for Digital Electronics.

1, 2 and 4 is the correct answer to “Consider the following statements describing the property of a complementary MOS (CMOS) inverter: 1. It is a combination of an n-channel FET and a p-channel FET. 2. There is power dissipation when the input carriers the logical 1 signal. 3. There is no power dissipation when the input carries the logic 1 signal. 4. There is power dissipation during transition from 0 to 1 or from 1 to 0. Which of the statements given above are correct:”. This question is standard in competitive examination syllabi for Digital Electronics.

3 is the correct answer to “For the Boolean expression $$\overline {\text{A}} {\text{BC}} + {\text{A}}\overline {\text{B}} {\text{C}} + {\text{AB}}\overline {\text{C}} {\text{,}}$$ how many 1's are in the output column of the truth table”. This question is standard in competitive examination syllabi for Digital Electronics.

$${\text{Y}} = \overline {\text{A}} \overline {\text{B}} + {\text{AB}} + \overline {\text{C}} $$ is the correct answer to “The Boolean expression for the output of the logic circuit shown in the figure is”. This question is standard in competitive examination syllabi for Digital Electronics.

2 is the correct answer to “With the availability of 16 × 4 memory size, how many ICs (memory chips) will be required for the expansion of its word size in order to obtain 16 × 8 memory”. This question is standard in competitive examination syllabi for Digital Electronics.

$${\text{J}} = \overline {\text{Y}} {\text{, K}} = {\text{X}}$$ is the correct answer to “An X-Y flip-flop, whose characteristic table is given below is to be implemented using J-K flip-flop. This can be done making X Y Q n+1 0 0 1 0 1 Q n 1 0 $${\overline {\text{Q}} _{\text{n}}}$$ 1 1 0”. This question is standard in competitive examination syllabi for Digital Electronics.

74194 is the correct answer to “The IC used for making a bidirectional universal shift register is-”. This question is standard in competitive examination syllabi for Digital Electronics.

$${\overline {\text{X}} }$$ is the correct answer to “The output Y of the circuit shown below is”. This question is standard in competitive examination syllabi for Digital Electronics.

01010010 is the correct answer to “Consider the bit pattern 01010001. Which of the following has Hamming distance of exactly 2 from these patterns”. This question is standard in competitive examination syllabi for Digital Electronics.

DE3 is the correct answer to “The 2's complement representation of (-541) 10 decimal in hexadecimal is:”. This question is standard in competitive examination syllabi for Digital Electronics.

8 is the correct answer to “The number of flip-flop required to construct an 8-bit shift register will be”. This question is standard in competitive examination syllabi for Digital Electronics.

AND is the correct answer to “Which of the following gates is also called 'all or nothing gate'”. This question is standard in competitive examination syllabi for Digital Electronics.

Active pull up and active pull down is the correct answer to “In TTL family, the Totem-pole circuit on the output is used to provide . . . . . . . .”. This question is standard in competitive examination syllabi for Digital Electronics.

X + Y is the correct answer to “The expression X + $$\overline {\text{X}} $$ ⋅ Y is equal to”. This question is standard in competitive examination syllabi for Digital Electronics.

+(2n - 1 - 1), -2n - 1 is the correct answer to “The maximum positive and negative numbers which can be represented in 2's complement form using n-bit are”. This question is standard in competitive examination syllabi for Digital Electronics.

10 is the correct answer to “The resolution of an-n-bit D/A converter with a maximum input of 5 V is 5 mV. The value of 'n' is”. This question is standard in competitive examination syllabi for Digital Electronics.

16 is the correct answer to “In a decoder, if the input lines are 4 then number of maximum output lines will be:”. This question is standard in competitive examination syllabi for Digital Electronics.

Both shift left and shift right operations can not be performed is the correct answer to “The disadvantage of an open shift register is that”. This question is standard in competitive examination syllabi for Digital Electronics.

$$\overline {\text{w}} {\text{x}}\overline {\text{y}} + \overline {\text{w}} {\text{yz}} + {\text{w}}\overline {\text{y}} {\text{z}} + {\text{wxy}}$$ is the correct answer to “What is the minimized logic expression corresponding to the given Karnaugh Map”. This question is standard in competitive examination syllabi for Digital Electronics.

a-3, b-2, c-5, d-4 is the correct answer to “Match List-I with List-II and select the correct answer using the options given below the lists: List-I (Logic Gates) List-II (Power dissipation per gate in mW) a. DTL 1. 55 b. TTL 2. 10 c. ECL 3. 8 d. MOS 4. 1 5. 40”. This question is standard in competitive examination syllabi for Digital Electronics.

Seven flip flops, largest decimal number is 63 is the correct answer to “How many flip flops are required to construct a MOD-128 counter? What is the largest decimal number that can be stored in a MOD-64 counter”. This question is standard in competitive examination syllabi for Digital Electronics.

37 is the correct answer to “(100101) 2 is equal to decimal number”. This question is standard in competitive examination syllabi for Digital Electronics.

Ripple counter is the correct answer to “In . . . . . . . ., the flip flop output transition serves as a source for triggering other flip-flops.”. This question is standard in competitive examination syllabi for Digital Electronics.

Nor is the correct answer to “The following circuit represents which logic”. This question is standard in competitive examination syllabi for Digital Electronics.

15.625 KHz is the correct answer to “A counter is designed with six stages of flip flops. Determine the output frequency at the last (sixth) stage, when input frequency is 1 MHz.”. This question is standard in competitive examination syllabi for Digital Electronics.

To control the location of diffusion and to protect and insulate the Si Surface is the correct answer to “Silicon dioxide is used in Ics”. This question is standard in competitive examination syllabi for Digital Electronics.

a-2, b-3, c-1 is the correct answer to “Match List-I with List-II and select the correct answer using the options given below the list: List-I List-II a. TTL 1. Low power consumption b. ECL 2. High speed c. CMOS 3. Low propagation delay”. This question is standard in competitive examination syllabi for Digital Electronics.

Bistable multivibrator is the correct answer to “Which of the following circuit exhibits memory”. This question is standard in competitive examination syllabi for Digital Electronics.

$${\text{F}} = {\text{W}} \oplus {{\text{S}}_1} \oplus {{\text{S}}_2}$$ is the correct answer to “Consider the multiplexer based logic circuit shown in the figure Which one of the following Boolean functions is realized by the circuit”. This question is standard in competitive examination syllabi for Digital Electronics.