Digital Electronics MCQ Questions with Brief Explanatory Answers

Digital Electronic systems play a prominent role in today’s digital age. Digital Electronics are widely employed in present-day industrial, scientific, and commercial applications such as communication, traffic control, business transactions, spacecraft guidance, medical treatment, weather monitoring, and the Internet. Given below are most important MCQ Questions on Digital Electronics with brief explanatory answers.

The binary digit also called a ___________, has _________ values

The binary digit also called a ___________, has _________ values:

1. Bit, Three
2. Bit, Two
3. Byte, Two
4. Byte, Three

Correct answer: 2. Bit, Two

Explanation: The signals employed in most modern day digital electronic systems use just two discrete values and are hence known as binary. A binary digit also called a bit, has two values: 0 and 1. Discrete elements of information are signified using groups of bits called binary codes.

The additive identity is

The additive identity is:

1. 0
2. 1
3. 2
4. 3

Correct answer: 2. 1

Explanation:

1 is the additive identity

Good to know

• The binary operator + describes addition
• The additive identity is 0
• The additive inverse defines subtraction
• The binary operator # defines multiplication
• The multiplicative identity is 1

Number of Gates in SSI devices is generally

Number of Gates in SSI devices is generally:

1. 2
2. Less than 10
3. 10 to 50
4. 50 to 1000

Correct answer: 2. Less than 10

Explanation: SSI is an abbreviation for Small‐scale integration. SSI devices comprise several independent gates in a single package. In such devices the inputs and outputs of gates are linked directly to the pins in the package. The number of gates in SSI devices is typically fewer than 10.

The abbreviation VLSI implies

The abbreviation VLSI implies:

1. Variable large-scale integration
2. Variable logical small integration
3. Variable logical scale integration
4. Very large-scale integration

Correct answer: 1. Very large-scale integration

Explanation: VLSI devices are very large‐scale integration that usually comprise millions of gates within a single package. The most popular examples of such devices contain complex microcomputer chips.

The number of gate inputs available are known as

The number of gate inputs available are known as:

1. Fan-in
2. Fan-out
3. Gate-in
4. Gate-out

Correct answer: 1. Fan-in

Explanation: In case of Digital Logic Design:

• The term fan-in implies number of inputs available in a gate.
• The term fan‐out implies the number of standard loads that the output of a typical gate can drive without impairing its normal operation.

Positive logic in a logic circuit is one in which

Positive logic in a logic circuit is one in which

1. Logic 0 voltage level is higher than logic 1 voltage level
2. Logic 0 voltage level is lower than logic 1 voltage level
3. Logic 0 and 1 are represented by 0 and positive voltage respectively
4. Logic 0 and, -1 are represented by negative and positive voltages respectively

Correct answer: 2. Logic 0 voltage level is lower than logic 1 voltage level

NAND gates are preferred over others since they

NAND gates are preferred over others since they:

1. Can be used to make any gate
2. Consume least electronic power
3. Have lower fabrication area
4. Provide maximum density in a chip

Correct answer: 1. Can be used to make any gate

An input signal 1 is applied to a NOT gate, the output will be

An input signal 1 is applied to a NOT gate, the output will be:

1. 0
2. 1
3. Either 0 or 1
4. of the above

Correct answer: 1. 0

Most of digital computers do not have floating point hardware since

Most of digital computers do not have floating point hardware since

1. Floating point hardware is uneconomical
2. It is not possible to perform floating point addition by hardware
3. It is slower than software
4. None of above

Correct answer: 1. Floating point hardware is uneconomical

The fan out of a 7400 NAND gate is

The fan out of a 7400 NAND gate is

1. 2TTL
2. 5TTL
3. 8TTL
4. 10TTL

Correct answer: 4. 10TTL

Explanation: The term fan-out implies number of gate inputs of same sub-family that a single output can drive. The fan out of 7400 NAND gate is 10.