Digital Electronics Solved MCQs

1.

Any number with an exponent of zero is equal to:

A. zero
B. one
C. that number
D. ten
Answer» B. one
2.

In the decimal numbering system, what is the MSD?

A. the middle digit of a stream of numbers
B. the digit to the right of the decimal point
C. the last digit on the right
D. the digit with the most weight
Answer» D. the digit with the most weight
3.

Which of the following statements does NOT describe an advantage of digital technology?

A. the values may vary over a continuous range.
B. the circuits are less affected by noise.
C. the operation can be programmed.
D. information storage is easy.
Answer» A. the values may vary over a continuous range.
4.

The generic array logic (GAL) device is ________.

A. one-time programmable
B. reprogrammable
C. a cmos device
D. reprogrammable and a cmos device
Answer» B. reprogrammable
5.

The range of voltages between VL(max) and VH(min) are ________.

A. unknown
B. unnecessary
C. unacceptable
D. between 2 v and 5 v
Answer» C. unacceptable
6.

What is a digital-to-analog converter?

A. it takes the digital information from an audio cd and converts it to a usable form.
B. it allows the use of cheaper analog techniques, which are always simpler.
C. it stores digital data on a hard drive.
D. it converts direct current to alternating current.
Answer» A. it takes the digital information from an audio cd and converts it to a usable form.
7.

What are the symbols used to represent digits in the binary number system?

A. 0,1
B. 0,1,2
C. 0 through 8
D. 1,2
Answer» A. 0,1
8.

A full subtracter circuit requires ________.

A. two inputs and two outputs
B. two inputs and three outputs
C. three inputs and one output
D. three inputs and two outputs
Answer» D. three inputs and two outputs
9.

The output of an AND gate is LOW ________.

A. all the time
B. when any input is low
C. when any input is high
D. when all inputs are high
Answer» B. when any input is low
10.

Give the decimal value of binary 10010.

A. 610
B. 910
C. 1810
D. 2010
Answer» C. 1810
11.

Parallel format means that:

A. each digital signal has its own conductor.
B. several digital signals are sent on each conductor.
C. both binary and hexadecimal can be used.
D. no clock is needed.
Answer» A. each digital signal has its own conductor.
12.

A decoder converts ________.

A. noncoded information into coded form
B. coded information into noncoded form
C. highs to lows
D. lows to highs
Answer» B. coded information into noncoded form
13.

A DAC changes ________.

A. an analog signal into digital data
B. digital data into an analog signal
C. digital data into an amplified signal
D. none of the above
Answer» B. digital data into an analog signal
14.

The output of a NOT gate is HIGH when ________.

A. the input is low
B. the input is high
C. the input changes from low to high
D. voltage is removed from the gate
Answer» A. the input is low
15.

The output of an OR gate is LOW when ________.

A. all inputs are low
B. any input is low
C. any input is high
D. all inputs are high
Answer» A. all inputs are low
16.

Which of the following is not an analog device?

A. thermocouple
B. current flow in a circuit
C. light switch
D. audio microphone
Answer» C. light switch
17.

A demultiplexer has ________.

A. one data input and a number of selection inputs, and they have several outputs
B. one input and one output
C. several inputs and several outputs
D. several inputs and one output
Answer» A. one data input and a number of selection inputs, and they have several outputs
18.

A flip-flop has ________.

A. one stable state
B. no stable states
C. two stable states
D. none of the above
Answer» C. two stable states
19.

Digital signals transmitted on a single conductor (and a ground) must be transmitted in:

A. slow speed.
B. parallel.
C. analog.
D. serial.
Answer» D. serial.
20.

In a certain digital waveform, the period is four times the pulse width. The duty cycle is ________.

A. 0%
B. 25%
C. 50%
D. 100%
Answer» B. 25%
21.

Select the statement that best describes the parity method of error detection:

A. parity checking is best suited for detecting double-bit errors that occur during the transmission of codes from one location to another.
B. parity checking is not suitable for detecting single-bit errors in transmitted codes.
C. parity checking is best suited for detecting single-bit errors in transmitted codes.
D. parity checking is capable of detecting and correcting errors in transmitted codes.
Answer» C. parity checking is best suited for detecting single-bit errors in transmitted codes.
22.

A logic circuit that provides a HIGH output for both inputs HIGH or both inputs LOW is a(n):

A. ex-nor gate
B. or gate
C. ex-or gate
D. nand gate
Answer» A. ex-nor gate
23.

A logic circuit that provides a HIGH output if one input or the other input, but not both, is HIGH, is a(n):

A. ex-nor gate
B. or gate
C. ex-or gate
D. nand gate
Answer» C. ex-or gate
24.

Identify the type of gate below from the equation

A. ex-nor gate
B. or gate
C. ex-or gate
D. nand gate
Answer» C. ex-or gate
25.

Parity systems are defined as either________ or ________ and will add an extra ________ tothe digital information being transmitted.

A. positive, negative, byte
B. odd, even, bit
C. upper, lower, digit
D. on, off, decimal
Answer» B. odd, even, bit
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