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    Discussion Question


    General Questions

    1).
    The output of an AND gate with three inputs, A, B, and C, is HIGH when ________.
    A   A = 1, B = 1, C = 0   
    B   A = 0, B = 0, C = 0   
    C   A = 1, B = 1, C = 1   
    D   A = 1, B = 0, C = 1   
    ANS: C - A = 1, B = 1, C = 1

    No answer description available for this question.

    2).
    If a 3-input NOR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?
    A   1   
    B   2   
    C   7   
    D   8   
    ANS: A - 1

    No answer description available for this question.

    3).
    If a signal passing through a gate is inhibited by sending a LOW into one of the inputs, and the output is HIGH, the gate is a(n):
    A   AND   
    B   NAND   
    C   NOR   
    D   OR   
    ANS: B - NAND

    No answer description available for this question.

    4).
    A device used to display one or more digital signals so that they can be compared to expected timing diagrams for the signals is a:
    A   DMM   
    B   spectrum analyzer   
    C   logic analyzer   
    D   frequency counter   
    ANS: C - logic analyzer

    No answer description available for this question

    5).
    When used with an IC, what does the term "QUAD" indicate?
    A   2 circuits   
    B   4 circuits   
    C   6 circuits   
    D   8 circuits   
    ANS: B - 4 circuits

    No answer description available for this question.

    6).
    The output of an OR gate with three inputs, A, B, and C, is LOW when ________.
    A   A = 0, B = 0, C = 0   
    B   A = 0, B = 0, C = 1   
    C   A = 0, B = 1, C = 1   
    D   all of the above   
    ANS: A - A = 0, B = 0, C = 0

    No answer description available for this question.

    7).
    Which of the following logical operations is represented by the + sign in Boolean algebra?
    A   inversion   
    B   AND   
    C   OR   
    D   complementation   
    ANS: C - OR

    No answer description available for this question.

    8).
    Output will be a LOW for any case when one or more inputs are zero for a(n):
    A   OR gate   
    B   NOT gate   
    C   AND gate   
    D   NOR gate   
    ANS: C - AND gate

    No answer description available for this question

    9).
    How many pins does the 4049 IC have?
    A   14   
    B   16   
    C   18   
    D   20   
    ANS: B - 16

    No answer description available for this question.

    10).
    Which of the following choices meets the minimum requirement needed to create specialized waveforms that are used in digital control and sequencing circuits?
    A   basic gates, a clock oscillator, and a repetitive waveform generator   
    B   basic gates, a clock oscillator, and a Johnson shift counter   
    C   basic gates, a clock oscillator, and a DeMorgan pulse generator   
    D   basic gates, a clock oscillator, a repetitive waveform generator, and a Johnson shift counter   
    ANS: A - basic gates, a clock oscillator, and a repetitive waveform generator

    No answer description available for this question

    11).
    TTL operates from a ________.
    A   9-volt supply   
    B   3-volt supply   
    C   12-volt supply   
    D   5-volt supply   
    ANS: D - 5-volt supply

    No answer description available for this question

    12).
    The output of a NOR gate is HIGH if ________.
    A   all inputs are HIGH   
    B   any input is HIGH   
    C   any input is LOW   
    D   all inputs are LOW   
    ANS: D - all inputs are LOW

    No answer description available for this question.

    13).
    The switching speed of CMOS is now ________.
    A   competitive with TTL   
    B   three times that of TTL   
    C   slower than TTL   
    D   twice that of TTL   
    ANS: A - competitive with TTL

    No answer description available for this question. 

    14).
    The format used to present the logic output for the various combinations of logic inputs to a gate is called a(n):
    A   Boolean constant   
    B   Boolean variable   
    C   truth table   
    D   input logic function   
    ANS: C - truth table

    No answer description available for this question.

    15).
    The power dissipation, PD, of a logic gate is the product of the ________.
    A   dc supply voltage and the peak current   
    B   dc supply voltage and the average supply current   
    C   ac supply voltage and the peak current   
    D   ac supply voltage and the average supply current   
    ANS: B - dc supply voltage and the average supply current

    No answer description available for this question.

    16).
    A logic probe is again applied to the pins of a 7421 IC with the following results. Is there a problem with the circuit and if so, what is the problem?
    A   Pin 6 should be ON.   
    B   Pin 8 should be ON.   
    C   Pin 8 should be pulsing.   
    D   no problem   
    ANS: D - no problem

    No answer description available for this question.

    17).
    If a 3-input AND gate has eight input possibilities, how many of those possibilities will result in a HIGH output?
    A   1   
    B   2   
    C   7   
    D   8   
    ANS: A - 1

    No answer description available for this question.

    18).
    The Boolean expression for a 3-input AND gate is ________.
    A   X = AB   
    B   X = ABC   
    C   X = A + B + C   
    D   X = AB + C   
    ANS: B - X = ABC

    No answer description available for this question.

    19).
    A CMOS IC operating from a 3-volt supply will consume ________.
    A   less power than a TTL IC   
    B   more power than a TTL IC   
    C   the same power as a TTL IC   
    D   no power at all   
    ANS: A - less power than a TTL IC

    No answer description available for this question

    20).
    What does the small bubble on the output of the NAND gate logic symbol mean?
    A   open collector output   
    B   tristate   
    C   The output is inverted.   
    D   none of the above   
    ANS: C - The output is inverted.

    No answer description available for this question.

    21).
    What are the pin numbers of the outputs of the gates in a 7432 IC?
    A   3, 6, 10, and 13   
    B   1, 4, 10, and 13   
    C   3, 6, 8, and 11   
    D   1, 4, 8, and 11   
    ANS: C - 3, 6, 8, and 11

    No answer description available for this question.

    22).
    The output of a NOT gate is HIGH when ________.
    A   the input is LOW   
    B   the input is HIGH   
    C   power is applied to the gate's IC   
    D   power is removed from the gate's IC   
    ANS: A - the input is LOW

    No answer description available for this question.

    23).
    If the input to a NOT gate is A and the output is X, then ________.
    A   X = A   
    B     
    C   X = 0   
    D   none of the above   
    ANS: B -

    No answer description available for this question.

    24).
    A logic probe is used to test the pins of a 7411 IC with the following results. Is there a problem with the chip and if so, what is the problem?
    A   Pin 6 should be ON.   
    B   Pin 6 should be pulsing.   
    C   Pin 8 should be ON.   
    D   no problem   
    ANS: B - Pin 6 should be pulsing.

    No answer description available for this question.

    25).
    How many inputs of a four-input AND gate must be HIGH in order for the output of the logic gate to go HIGH?
    A   any one of the inputs   
    B   any two of the inputs   
    C   any three of the inputs   
    D   all four inputs   
    ANS: D - all four inputs

    No answer description available for this question.

    26).
    If the output of a three-input AND gate must be a logic LOW, what must the condition of the inputs be?
    A   All inputs must be LOW.   
    B   All inputs must be HIGH.   
    C   At least one input must be LOW.   
    D   At least one input must be HIGH.   
    ANS: C - At least one input must be LOW.

    No answer description available for this question. 

    27).
    Logically, the output of a NOR gate would have the same Boolean expression as a(n):
    A   NAND gate immediately followed by an inverter   
    B   OR gate immediately followed by an inverter   
    C   AND gate immediately followed by an inverter   
    D   NOR gate immediately followed by an inverter   
    ANS: B - OR gate immediately followed by an inverter

    No answer description available for this question.

    28).
    A logic probe is placed on the output of a gate and the display indicator is dim. A pulser is used on each of the input terminals, but the output indication does not change. What is wrong?
    A   The dim indication on the logic probe indicates that the supply voltage is probably low.   
    B   The output of the gate appears to be open.   
    C   The dim indication is the result of a bad ground connection on the logic probe.   
    D   The gate is a tristate device.   
    ANS: B - The output of the gate appears to be open.

    No answer description available for this question.

    29).
    What is the Boolean expression for a three-input AND gate?
    A   X = A + B + C   
    B   X = A · B · C   
    C   A – B – C   
    D   A $ B $ C   
    ANS: B - X = A · B · C

    No answer description available for this question.

    30).
    Which of the following gates has the exact inverse output of the OR gate for all possible input combinations?
    A   NOR   
    B   NOT   
    C   NAND   
    D   AND   
    ANS: A - NOR

    No answer description available for this question.

    31).
    What is the difference between a 7400 and a 7411 IC?
    A   7400 has two four-input NAND gates; 7411 has three three-input AND gates   
    B   7400 has four two-input NAND gates; 7411 has three three-input AND gates   
    C   7400 has two four-input AND gates; 7411 has three three-input NAND gates   
    D   7400 has four two-input AND gates; 7411 has three three-input NAND gates   
    ANS: B - 7400 has four two-input NAND gates; 7411 has three three-input AND gates

    No answer description available for this question.

    32).
    Write the Boolean expression for an inverter logic gate with input C and output Y.
    A   Y = C   
    B   Y =    
    ANS: B - Y = 

    No answer description available for this question.

    33).
    The output of an exclusive-OR gate is HIGH if ________.
    A   all inputs are LOW   
    B   all inputs are HIGH   
    C   the inputs are unequal   
    D   none of the above   
    ANS: C - the inputs are unequal

    No answer description available for this question.

    34).
    A clock signal with a period of 1 s is applied to the input of an enable gate. The output must contain six pulses. How long must the enable pulse be active?
    A   Enable must be active for 0 s.   
    B   Enable must be active for 3 s.   
    C   Enable must be active for 6 s.   
    D   Enable must be active for 12 s.   
    ANS: C - Enable must be active for 6 s.

    No answer description available for this question.

    35).
    The AND function can be used to ________ and the OR function can be used to ________ .
    A   enable, disable   
    B   disable, enable   
    C   enable or disable, enable or disable   
    D   detect, invert   
    ANS: C - enable or disable, enable or disable

    No answer description available for this question.

    36).
    One advantage TTL has over CMOS is that TTL is ________.
    A   less expensive   
    B   not sensitive to electrostatic discharge   
    C   faster   
    D   more widely available   
    ANS: B - not sensitive to electrostatic discharge

    No answer description available for this question.

    37).
    A 2-input NOR gate is equivalent to a ________.
    A   negative-OR gate   
    B   negative-AND gate   
    C   negative-NAND gate   
    D   none of the above   
    ANS: B - negative-AND gate

    No answer description available for this question

    38).
    If a 3-input OR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?
    A   1   
    B   2   
    C   7   
    D   8   
    ANS: C - 7

    No answer description available for this question.

    39).
    Fan-out is specified in terms of ________.
    A   voltage   
    B   current   
    C   wattage   
    D   unit loads   
    ANS: D - unit loads

    No answer description available for this question.

    40).
    How many input combinations would a truth table have for a six-input AND gate?
    A   32   
    B   48   
    C   64   
    D   128   
    ANS: C - 64

    No answer description available for this question.

    41).
    What is the circuit number of the IC that contains four two-input AND gates in standard TTL?
    A   7402   
    B   7404   
    C   7408   
    D   7432   
    ANS: C - 7408

    No answer description available for this question. 

    42).
    The terms "low speed" and "high speed," applied to logic circuits, refer to the ________.
    A   rise time   
    B   fall time   
    C   propagation delay time   
    D   clock speed   
    ANS: C - propagation delay time

    No answer description available for this question. 

    43).
    The NOR logic gate is the same as the operation of the ________ gate with an inverter connected to the output.
    A   OR   
    B   AND   
    C   NAND   
    D   none of the above   
    ANS: A - OR

    No answer description available for this question.

    44).
    The logic expression for a NOR gate is ________.
    A     
    B     
    C     
    D     
    ANS: D -

    No answer description available for this question

    45).
    With regard to an AND gate, which statement is true?
    A   An AND gate has two inputs and one output.   
    B   An AND gate has two or more inputs and two outputs.   
    C   If one input to a 2-input AND gate is HIGH, the output reflects the other input.   
    D   A 2-input AND gate has eight input possibilities.   
    ANS: C - If one input to a 2-input AND gate is HIGH, the output reflects the other input.

    No answer description available for this question.

    46).
    The term "hex inverter" refers to:
    A   an inverter that has six inputs   
    B   six inverters in a single package   
    C   a six-input symbolic logic device   
    D   an inverter that has a history of failure   
    ANS: B - six inverters in a single package

    No answer description available for this question.

    47).
    How many inputs are on the logic gates of a 74HC21 IC?
    A   1   
    B   2   
    C   3   
    D   4   
    ANS: D - 4

    No answer description available for this question. 

    48).
    The basic logic gate whose output is the complement of the input is the:
    A   OR gate   
    B   AND gate   
    C   inverter   
    D   comparator   
    ANS: C - inverter

    No answer description available for this question.

    49).
    When reading a Boolean expression, what does the word "NOT" indicate?
    A   the same as   
    B   inversion   
    C   high   
    D   low   
    ANS: B - inversion

    No answer description available for this question.

    50).
    The output of an exclusive-NOR gate is HIGH if ________.
    A   the inputs are equal   
    B   one input is HIGH, and the other input is LOW   
    C   the inputs are unequal   
    D   none of the above   
    ANS: A - the inputs are equal

    No answer description available for this question.

    51).
    How many AND gates are found in a 7411 IC?
    A   1   
    B   2   
    C   3   
    D   4   
    ANS: C - 3

    No answer description available for this question.

    52).
    Which of the following equations would accurately describe a four-input OR gate when A = 1, B = 1, C = 0, and D = 0?
    A   1 + 1 + 0 + 0 = 01   
    B   1 + 1 + 0 + 0 = 1   
    C   1 + 1 + 0 + 0 = 0   
    D   1 + 1 + 0 + 0 = 00   
    ANS: B - 1 + 1 + 0 + 0 = 1

    No answer description available for this question. 

    53).
    What is the name of a digital circuit that produces several repetitive digital waveforms?
    A   an inverter   
    B   an OR gate   
    C   a Johnson shift counter   
    D   an AND gate   
    ANS: C - a Johnson shift counter

    No answer description available for this question.

    54).
    The basic types of programmable arrays are made up of ________.
    A   AND gates   
    B   OR gates   
    C   NAND and NOR gates   
    D   AND gates and OR gates   
    ANS: D - AND gates and OR gates

    No answer description available for this question.

    55).
    The logic gate that will have HIGH or "1" at its output when any one (or more) of its inputs is HIGH is a(n):
    A   OR gate   
    B   AND gate   
    C   NOR gate   
    D   NOT operation   
    ANS: A - OR gate

    No answer description available for this question.

    56).
    CMOS IC packages are available in ________.
    A   DIP configuration   
    B   SOIC configuration   
    C   DIP and SOIC configurations   
    D   neither DIP nor SOIC configurations   
    ANS: C - DIP and SOIC configurations

    No answer description available for this question.

    57).
    Which of the following is not a basic Boolean operation?
    A   OR   
    B   NOT   
    C   AND   
    D   FOR   
    ANS: D - FOR

    No answer description available for this question.

    58).
    Which of the following gates is described by the expression ?
    A   OR   
    B   AND   
    C   NOR   
    D   NAND   
    ANS: D - NAND

    No answer description available for this question

    59).
    What is the Boolean expression for a four-input OR gate?
    A   Y = A + B + C + D   
    B   Y = A· B · C · D   
    C   Y = A – B – C – D   
    D   Y = A $ B $ C $ D   
    ANS: A - Y = A + B + C + D

    No answer description available for this question. 

    60).
    How many truth table entries are necessary for a four-input circuit?
    A   4   
    B   8   
    C   12   
    D   16   
    ANS: D - 16

    No answer description available for this question.

    61).
    How many entries would a truth table for a four-input NAND gate have?
    A   2   
    B   8   
    C   16   
    D   32   
    ANS: C - 16

    No answer description available for this question.

    62).
    The Boolean expression for a 3-input OR gate is ________.
    A   X = A + B   
    B   X = A + B + C   
    C   X = ABC   
    D   X = A + BC   
    ANS: B - X = A + B + C

    No answer description available for this question.

    63).
    From the truth table for a three-input NOR gate, what is the only condition of inputs A, B, and C that will make the output X high?
    A   A = 1, B = 1, C = 1   
    B   A = 1, B = 0, C = 0   
    C   A = 0, B = 0, C = 1   
    D   A = 0, B = 0, C = 0   
    ANS: D - A = 0, B = 0, C = 0

    No answer description available for this question.

    64).
    The logic gate that will have a LOW output when any one of its inputs is HIGH is the:
    A   NAND gate   
    B   AND gate   
    C   NOR gate   
    D   OR gate   
    ANS: C - NOR gate

    No answer description available for this question.

    65).
    The output of a NAND gate is LOW if ________.
    A   all inputs are LOW   
    B   all inputs are HIGH   
    C   any input is LOW   
    D   any input is HIGH   
    ANS: B - all inputs are HIGH

    No answer description available for this question.