## digital concepts

#### Discussion Question

General Questions

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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).

###### 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.

###### 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.

###### 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.

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

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###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### Convert the fractional binary number 0000.1010 to decimal.
 A 0.625 B 0.5 C 0.55 D 0.1
 ANS: A - 0.625

No answer description available for this question.

###### 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.

###### 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.

###### 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.

###### Convert the fractional decimal number 6.75 to binary.
 A 111.11 B 110.101 C 110.11 D 110.011
 ANS: C - 110.11

No answer description available for this question.

###### 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.

###### 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.

###### 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

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

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###### 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.

###### 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

###### 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.

###### What is the decimal value of 23 ?
 A 2 B 4 C 6 D 8
 ANS: D - 8

2= 2*2*2=8

###### 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.

###### 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.

###### 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.

###### 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.

###### Convert the fractional binary number 0001.0010 to decimal.
 A 1.4 B 1.125 C 1.2 D 1.8
 ANS: B - 1.125

No answer description available for this question.

###### Convert the fractional binary number 10010.0100 to decimal.
 A 24.5 B 18.25 C 18.4 D 16.25
 ANS: B - 18.25

No answer description available for this question.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

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

No answer description available for this question

###### 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.

###### 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.

###### 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.

###### 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.

###### 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.

###### 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

###### 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.