digital concepts



General Questions

1).
Any number with an exponent of zero is equal to:
A   zero   
B   one   
C   that number   
D   ten   
ANS: B - one

No answer description available for this question.

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   
ANS: D - The digit with the most weight

No answer description available for this question.

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.   
ANS: A - The values may vary over a continuous range.

No answer description available for this question.

4).
The generic array logic (GAL) device is ________.
A   one-time programmable   
B   reprogrammable   
C   a CMOS device   
D   reprogrammable and a CMOS device   
ANS: B - reprogrammable

No answer description available for this question.

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   
ANS: C - unacceptable

No answer description available for this question.

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.   
ANS: A - It takes the digital information from an audio CD and converts it to a usable form.

A DAC converts an abstract finite-precision number (usually a fixed-point binary number) into a concrete physical quantity (e.g., a voltage or a pressure).

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   
ANS: A - 0,1

No answer description available for this question.

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   
ANS: D - three inputs and two outputs

No answer description available for this question.

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   
ANS: B - when any input is LOW

No answer description available for this question.

10).
Give the decimal value of binary 10010.
A   610   
B   910   
C   1810   
D   2010   
ANS: C - 1810

No answer description available for this question.

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.   
ANS: A - each digital signal has its own conductor.

No answer description available for this question. 

12).
A decoder converts ________.
A   noncoded information into coded form   
B   coded information into noncoded form   
C   HIGHs to LOWs   
D   LOWs to HIGHs   
ANS: B - coded information into noncoded form

No answer description available for this question.

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   
ANS: B - digital data into an analog signal

No answer description available for this question.

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   
ANS: A - the input is LOW

No answer description available for this question.

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   
ANS: A - all inputs are LOW

No answer description available for this question.

16).
Which of the following is not an analog device?
A   Thermocouple   
B   Current flow in a circuit   
C   Light switch   
D   Audio microphone   
ANS: C - Light switch

No answer description available for this question.

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   
ANS: A - one data input and a number of selection inputs, and they have several outputs

No answer description available for this question.

18).
A flip-flop has ________.
A   one stable state   
B   no stable states   
C   two stable states   
D   none of the above   
ANS: C - two stable states

No answer description available for this question.

19).
Digital signals transmitted on a single conductor (and a ground) must be transmitted in:
A   slow speed.   
B   parallel.   
C   analog.   
D   serial.   
ANS: D - serial.

No answer description available for this question. 

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%   
ANS: B - 25%

No answer description available for this question.

21).
In positive logic, ________.
A   a HIGH = 1, a LOW = 0   
B   a LOW = 1, a HIGH = 0   
C   only HIGHs are present   
D   only LOWs are present   
ANS: A - a HIGH = 1, a LOW = 0

No answer description available for this question.

22).
Convert the fractional binary number 0000.1010 to decimal.
A   0.625   
B   0.50   
C   0.55   
D   0.10   
ANS: A - 0.625

No answer description available for this question.

23).
Digital representations of numerical values of quantities may BEST be described as having characteristics:
A   that are difficult to interpret because they are continuously changing.   
B   that vary constantly over a continuous range of values.   
C   that vary in constant and direct proportion to the values they represent.   
D   that vary in discrete steps in proportion to the values they represent.   
ANS: D - that vary in discrete steps in proportion to the values they represent.

No answer description available for this question.

24).
A common instrument used in troubleshooting a digital circuit is a(n) ________.
A   logic probe   
B   oscilloscope   
C   pulser   
D   all of the above   
ANS: D - all of the above

No answer description available for this question.

25).
The parallel transmission of digital data:
A   is much slower than the serial transmission of data.   
B   requires only one signal line between sender and receiver.   
C   requires as many signal lines between sender and receiver as there are data bits.   
D   is less expensive than the serial method of data transmission.   
ANS: C - requires as many signal lines between sender and receiver as there are data bits.

No answer description available for this question. 

26).
Convert the fractional decimal number 6.75 to binary.
A   0111.1100   
B   0110.1010   
C   0110.1100   
D   0110.0110   
ANS: C - 0110.1100

No answer description available for this question. 

27).
What is one relative disadvantage of serial transfer?
A   It requires too many conductors.   
B   Its interconnect system is complex.   
C   It is slow.   
D   It can only be used over very short distances.   
ANS: C - It is slow.

No answer description available for this question.

28).
Which format requires fewer conductors?
A   Parallel   
B   Serial   
C   Both are the same   
D   Cannot tell   
ANS: B - Serial

No answer description available for this question.

29).
A pulse has a period of 15 ms. Its frequency is ________.
A   6.66 Hz   
B   66.66 Hz   
C   666.66 Hz   
D   15 Hz   
ANS: B - 66.66 Hz

No answer description available for this question.

30).
Give the decimal value of binary 10000110.
A   13410   
B   14410   
C   11010   
D   12610   
ANS: A - 13410

No answer description available for this question.

31).
The rise time is the time it takes a pulse to go from ________.
A   the base line to the maximum HIGH voltage   
B   10% of the pulse amplitude to the maximum HIGH voltage   
C   the base line to 90% of the pulse amplitude   
D   10% of the pulse amplitude to 90% of the pulse amplitude   
ANS: D - 10% of the pulse amplitude to 90% of the pulse amplitude

No answer description available for this question.

32).
What is an analog-to-digital converter?
A   It makes digital signals.   
B   It takes analog signals and puts them in digital format.   
C   It allows the use of digital signals in everyday life   
D   It stores information on a CD.   
ANS: B - It takes analog signals and puts them in digital format.

No answer description available for this question

33).
A multiplexer has ________.
A   one input and several outputs   
B   one input and one output   
C   several inputs and several outputs   
D   several inputs and one output   
ANS: D - several inputs and one output

No answer description available for this question.

34).
What is the decimal value of 2?
A   2   
B   4   
C   6   
D   8   
ANS: D - 8

2= 2*2*2=8

35).
An encoder converts ________.
A   noncoded information into coded form   
B   coded information into noncoded form   
C   HIGHs to LOWs   
D   LOWs to HIGHs   
ANS: A - noncoded information into coded form

No answer description available for this question.

36).
What kind of logic device or circuit is used to store information?
A   Counter   
B   Register   
C   Inverter   
D   Buffer   
ANS: B - Register

No answer description available for this question.

37).
PLCC packages have leads on ________.
A   one side   
B   two sides   
C   three sides   
D   four sides   
ANS: D - four sides

No answer description available for this question.

38).
What is the typical invalid voltage for a binary signal?
A   0.7–2.8 volts   
B   0.8–3 volts   
C   0.8–2 volts   
D   0.7–2.5 volts   
ANS: C - 0.8–2 volts

No answer description available for this question.

39).
Convert the fractional binary number 0001.0010 to decimal.
A   1.40   
B   1.125   
C   1.20   
D   1.80   
ANS: B - 1.125

No answer description available for this question. 

40).
Convert the fractional binary number 10010.0100 to decimal.
A   24.50   
B   18.25   
C   18.40   
D   16.25   
ANS: B - 18.25

No answer description available for this question. 

41).
How many binary bits are necessary to represent 748 different numbers?
A   9   
B   7   
C   10   
D   8   
ANS: C - 10

No answer description available for this question.

42).
A periodic digital waveform has a pulse width (tw) of 6 ms and a period (T) of 18 ms. The duty cycle is ________.
A   3.3%   
B   33.3%   
C   6%   
D   18%   
ANS: B - 33.3%

No answer description available for this question.

43).
Any number with an exponent of one is equal to:
A   zero   
B   one   
C   two   
D   that number   
ANS: D - that number

No answer description available for this question.

44).
Serial format means digital signals are:
A   sent over many conductors simultaneously.   
B   sent over one conductor sequentially.   
C   sent in groups of eight signals.   
D   sent in binary coded decimal.   
ANS: B - sent over one conductor sequentially.

No answer description available for this question.

45).
What is the decimal value of 2–1 ?
A   0.5   
B   0.25   
C   0.05   
D   0.1   
ANS: A - 0.5

No answer description available for this question.

46).
Which format can send several bits of information faster?
A   Parallel   
B   Serial   
C   Both are the same   
D   Cannot tell   
ANS: A - Parallel

No answer description available for this question. 

47).
The frequency of a pulse train is 2 kHz. The pulse period is ________.
A   5 ms   
B   50 ms   
C   500 s   
D  s   
ANS: C - 500 s

No answer description available for this question

48).
What has happened to the advances in digital technologies over the past three decades?
A   Slowed down considerably   
B   Continued to increase, but at a decreasing rate   
C   Made excellent progress   
D   Nothing short of phenomenal   
ANS: D - Nothing short of phenomenal

No answer description available for this question.

49).
A type of digital circuit technology that uses bipolar junction transistors is ________.
A   TTL   
B   CMOS   
C   LSI   
D   NMOS   
ANS: A - TTL

No answer description available for this question.

50).
How many unique symbols are used in the decimal number system?
A   One   
B   Nine   
C   Ten   
D   Unlimited   
ANS: C - Ten

No answer description available for this question.

51).
A classification of ICs with complexities of 12 to 100 equivalent gates on a chip is known as ________.
A   SSI   
B   MSI   
C   LSI   
D   VLSI   
ANS: B - MSI

No answer description available for this question.

52).
Which of the following is a semiconductor memory?
A   RAM   
B   MAR   
C   CD-ROM   
D   CD   
ANS: A - RAM

No answer description available for this question.

53).
The holes through a PC board are ________.
A   smaller with SMT than with through-hole mounting   
B   larger with SMT than with through-hole mounting   
C   the same size as with through-hole mounting   
D   usually unnecessary   
ANS: C - the same size as with through-hole mounting

No answer description available for this question

54).
A classification of ICs with complexities of 100 to 10,000 equivalent gates per chip is known as ________.
A   SSI   
B   MSI   
C   LSI   
D   VLSI   
ANS: C - LSI

No answer description available for this question.