Download Digital Electronics - Test bank of Questions and Problems In order to

Digital Electronics - Test bank of Questions and
Problems
1. In order to function, each electrical loop (or circuit) requires:
a. Voltage, current, resistance
b. Power, watts, capacitance, inductance
c. Source, path and load
d. Proton, neutron, electron
2. Draw the pie chart for Ohm’s Law:
3. A resistor having a color code of Red, Red, Brown, Silver is rated at how many ohms of
resistance?
a. 20000 ohms
b. 220000 ohms
c. 22 ohms
d. 220 ohms
4. The same resistor, when measured with a multi-meter, is found to provide 180 ohms.
Should it be used (is the resistor in tolerance?)
5. An insulator has ______ electrons in it’s valence shell and _______ allow electricity to
flow through it.
a. 0-3/will not
b. 5-8/will
c. 0-3/will
d. 5-8/will not
6. The digital multimeter you have used in the lab will measure the following: (check all
that apply)
a. Voltage
b. Power
c. Watts
d. Current
e. Protons
f. Neutrons
g. Resistance
h. Inductance
i. Source
j. Tolerance
7. Batteries will typically provide what type of current?
a. Amps
b. Alternating
c. Digital
d. Direct
8. A series circuit is one in which
a. There is only one path through the circuit
b. There are multiple paths through the circuit
c. There is no path through the circuit
9. A parallel circuit is one in which
a. There is only one path through the circuit
b. There are multiple paths through the circuit
c. There is no path through the circuit
10. An open circuit is one in which
a. There is only one path through the circuit
b. There are multiple paths through the circuit
c. There is no path through the circuit
11. In the following circuit us Ohm’s Law to find the voltage
XMM1
8.000m A
V1
R2
R1
500Ω
1kΩ
12. In the following circuit use Ohm’s Law to find the current.
XMM1
V1
24V
R2
R1
50Ω
250Ω
13. Use Ohm’s Law to find the Resistance.
XMM1
6.000 m A
V1
12V
R1
2kΩ
14. In order to measure voltage, the multi-meter must be placed in series/parallel to the
circuit.
15. In order to measure current, the multi-meter probes must be placed in series/parallel to
the circuit.
16. If a logic state is said to be true, how is it represented in binary terms?
a. High
b. Low
c. Zero
d. One
17. If a logic statement is said to be false, how is it represented in digital terms?
a. High
b. Low
c. Zero
d. One
18. In what role does the path play in a circuit?
19. What role does the load play in a circuit?
20. Which of the following terms can be described as the pressure forcing the electricity through
the circuit?
a.
b.
c.
d.
Current
Voltage
Resistance
Capacitance
21. Which of the following terms can be best described as the total opposition to current
flow in a circuit?
a. Current
b. Voltage
c. Resistance
d. Capacitance
22. Which of the following terms can best be described as the total amount of electrons
flowing through a circuit at a given time?
a. Current
b. Voltage
c. Resistance
d. Capacitance
23. Name a digital system: __________________________________________________
24. The major difference between digital and analog signals lie in the fact that
a. Digital Signals can vary between many values and analog cannot
b. Digital signals do not yet exist
c. Digital signals vary only between two values
d. Analog signals can be only either high or low
25. The ____________ is a common tool to examine the waveform of a given signal
26. Which tool can instantly tell you the logic state existing anywhere in a circuit?
a. Logic Probe
b. Oscilloscope
c. Ammeter
d. Radial Arm Saw
27. Binary 11011 is equal to decimal
a. 13
b. 9
c. 27
d. 15
28. What is the BCD Equivalent of the decimal number 492
a. 1001 1110 1010
b. 0100 1001 0010
c. 1100 1000 0010
d. 0100 1101 0100
29. What is the hexadecimal equivalent of binary 10?
a. 4
b. 3
c. 2
d. 1
30. How many hexadecimal digits are needed to represent an 8 bit binary number?
a. 4
b. 3
c. 2
d. 1
31. Which of the following BCD number equals 763 in decimal form?
a. 0111 0110 0011
b. 1011 0101 0100
c. 1010 1101 1110
d. 1010 1011 1100
32. In binary addition, 1101 + 1011 equals
a. 10001
b. 11100
c. 11000
d. 10000
33. The hexadecimal equivalent of a decimal 13 is
a. A
b. B
c. C
d. D
34. When the bits of a four bit binary word are all shifted simultaneously from a high order
position to a lower order position the number is
a. Saved in its current form
b. Multiplied by 2
c. Divided by 2
d. Changed to it’s one complement
35. Digital electronics is based on which number system?
a. Decimal
b. Binary
c. Hexadecimal
d. Octal
36. BCD number 1001 0011 corresponds to the decimal number
a. 93
b. 10013
c. 43
d. 32
37. A groups of bits is called a
a. Numbering system
b. Circuit
c. Word
d. Byte
38. A digital BCD encoder converts a
a. Binary number to a decimal number
b. Decimal number to a binary number
c. A hexadecimal number to a binary number
d. Binary number to a BCD number
39. The ___________ number system uses only digits 0 thru 7
a. Hexadecimal
b. Octal
c. Decimal
d. Binary
40. The one carry results at the output of an adder when ________ are added together.
a. 10
b. 01
c. 00
d. 11
41. If the binary numbers 1001 and 0110 are added together the BCD answer is
a. 0001 0101
b. 01111
c. 1100 0111
d. 0101 0001
42. The one’s complement of binary 1010 is
a. 1011
b. 1010 + 1
c. 1111
d. 0101
43. The Two’s complement of binary 1100 is
a. 0011
b. 1100 + 1
c. 0100
d. 0101
44. The binary equivalent of hexadecimal 22 is
a. 100010
b. 10110
c. A5
d. 101001
45. BCD used a ______ bit word to represent decimal digits 0 through 9
a. 1
b. 2
c. 4
d. 8
46. The Octal number 23 corresponds to the binary number
a. 0010 0011
b. 11011
c. 10011
d. 10111
47. Complete the following conversion chart
Decimal
Binary
Octal
Hexadecimal
22
1100111
54
A2
48. The circuit to the right is equivalent to a(n)
a. OR gate
b. AND gate
c. NOR gate
d. NAND gate
49. If both inputs to a NAND gate are one, the output is
a. Logic one
b. Logic zero
c. GND
d. An indeterminate state
50. A 2 input OR gate has a logic zero output when
a. One input is low
b. Both inputs are low
c. One input is high
d. Both inputs are high
51. An OR gate with inverters at all inputs and output performs what function?
a. AND
b. OR
c. NOR
d. NAND
52. An AND gate with inverters at all of the inputs is equivalent to a(n)
a. NOR
b. NAND
c. AND
d. Not circuit
53. An _____________ gate is equivalent to an OR gate with an inverted output
a. NOR gate
b. NAND gate
c. AND gate
d. NOT Circuit
54. A NAND gate has an output of of logic 1 when
a. At least one input is a one
b. All inputs are 1
c. At least one input is 0
55. A 2 input exclusive OR gate compares two inputs and has a logic 1 output when
a. One input is 0
b. One input is 1
c. Both inputs are the same
d. Both inputs are different
56. In the circuit Below, What input combination would cause the output to be high?
A
B
a.
b.
c.
d.
00
01
11
Any combination
57. The circuit above performs the same function as:
a.
b.
c.
d.
58. A logic gate is the equivalent of a(n)
a. Amplifier
b. Oscillator
c. Buffer
d. Electromechanical switch
59. The logic OR gate is equivalent to
a. Switches in series
b. Switches in parallel
c. A series parallel mix
d. None of the above
60. A single input logic gate whose output is the complement of the input is a
a. Buffer
b. Inverter
c. NAND gate
d. NOR gate
61. In the circuit below, the output is 1 when
a.
b.
c.
d.
Both inputs are 1
Both inputs are 0
Either input is 1
The inputs are different
62. The circuit is question 62 is equal to
a.
b.
c.
d.
63. The truth table below is for a(n)
a. AND gate
b. OR gate
c. NAND gate
d. NOR gate
64. A four input NAND gate with a 0 output indicates that
a. One input is 1
b. One input is 0
c. All inputs are 1
d. All inputs are 0
65. A four input exclusive OR gate has a high input when
a. An odd number of inputs are high
b. An even number of inputs are high
c. An odd number of inputs are low
d. An even number of inputs are low
66. The truth table below is for a(n)
a. XOR gate
b. OR gate
c. NAND gate
d. NOR gate
67. The symbol for an AND gate is
a.
b.
c.
d.
68. For each of the following gates, draw the logic symbol, write the Boolean expression and
complete the truth table for a two input gate
AND
OR
NAND
NOR
69. Describe enable and inhibit as they pertain to logic gates
70. What is the function of the following integrated circuits
a. 4030=__________________________
b. 4002=__________________________
c. 4001=__________________________
d. 7402=__________________________
e. 7404=__________________________
f. 7432=__________________________
71. How do you convert an OR gate to an AND gate?
72. What three input logic gates would you use if you wanted a high output ONLY when one
of more inputs was low?
73. What input logic gate would you use if you wanted a low output when an odd number
of inputs were high?
74. Fanout is a term that refers to
a. An indication of a high level output
b. The number of loads that a device can drive
c. A type of surface mount technology
d. Time delay
75. When 1.8 V is applied to a TTL input it is interpreted by the integrated circuit as a logic
level
a. High
b. Low
c. Undefined
d. None of the above
76. A TTL gate with a high output would typically be about _______ Volts
a. 0.2
b. 0.9
c. 2.2
d. 3.6
77. Unwanted voltages induced in the connecting wires and the printed circuit board traces
of a digital system that might possibly affect its operation are called
a. Junk
b. Noise
c. Flux
d. Clutter
78. The logic family with excellent noise immunity is
a. CMOS
b. TTL
c. DDL
d. RTL
79. When storing CMOS family integrated circuit chips the pins should be in
a. Conductive foam
b. Water
c. Alcohol
d. Styrofoam
80. The standard TTL family of integrated circuits chips has very
a. Low propagation delays and low power consumption
b. High propagation delays and high power consumption
c. Low propagation delays and high power consumption
d. High propagation delays and low power consumption
81. A TTL output can drive a CMOS input with the addition of a
a. Pull-up resistor
b. Input capacitor
c. Debounce switch
d. Decoder
82. On a standard TTL data sheet which of the following is not found
a. Supply voltage
b. Pin layout
c. Recommended operating conditions
d. Component cost
83. ______________ is the design of circuitry between devices that shift voltage and
current levels to make them compatible
a. Propagation delay
b. Operating conditions
c. Logic levels
d. Interfacing
84. This particular type of integrated circuit is sensitive to static electricity
a. TTL
b. CMOS
c. ECL
d. MOS
85. A TTL output of 0.6 V is considered a
a. Low output
b. High output
c. Undefined
d. None of the above
86. A 4000 series CMOS output can drive a standard TTL inout with the addition of a
a. Buffer (such as a 4049)
b. Pull-up resistor
c. Pull-down resistor
d. Debounce switch
87. The switching threshold when applied to the inputs for a standard TTL logic gate inputs
is
a. About 1.0 V
b. Exactly 0.5 V
c. Between 0.5 and 1.0 V
d. Exactly 2.4 V
88. The fan out for standard TTL is ___________ when driving other TTL gates.
a. 2
b. 6
c. 8
d. 10
99. Using the simulator, design a circuit which interfaces a standard TTL device to a buzzer.
One Example:
VCC
5V
100.
Design, simulate and construct a circuit that when the key is in the ignition of a
car a buzzer will go off, until the seatbelt is buckled and the doors are closes. (There will
be a high output from the sensors when the key is in the ignition and the doors are
closed.) Develop a truth table which would indicate when the alarm sounds (a high
condition). From the truth table develop the Boolean expression, simplify that equation,
and verify the circuit using the simulation software. Construct and test the circuit by
breadboarding.
101.
Which is the correct truth table for the Boolean expression A + B?
a.
A
B
A+B
0
0
1
0
1
0
1
0
0
0
0
0
b.
A
B
A+B
0
0
0
0
1
1
1
0
1
0
0
1
c.
A
B
A+B
0
0
0
0
1
1
1
0
0
0
0
1
d.
A
B
A+B
0
0
0
0
1
0
1
0
0
0
0
1
102.
Which is the correct truth table for the Boolean expression A * B?
a.
A
B
A+B
0
0
1
0
1
0
1
0
0
0
0
0
b.
A
B
A+B
0
0
0
0
1
1
1
0
1
0
0
1
c.
A
B
A+B
0
0
0
0
1
1
1
0
0
0
0
1
d.
A
B
A+B
0
0
0
0
1
0
1
0
0
0
0
1
103.
Which is the correct truth table for the Boolean expression (A + B)?
a.
A
B
(A + B)
0
0
1
0
1
0
1
0
0
0
0
0
b.
A
B
(A + B)
0
0
0
0
1
1
1
0
1
0
0
1
c.
A
B
(A + B)
0
0
0
0
1
1
1
0
0
0
0
1
d.
A
B
(A + B)
0
0
0
0
1
0
1
0
0
0
0
1
104.
Which is the correct truth table for the Boolean expression A + B’?
a.
A
B
A+B
0
0
1
0
1
0
1
0
1
0
0
0
b.
A
B
A+B
0
0
0
0
1
1
1
0
1
0
0
1
c.
A
B
A+B
0
0
1
0
1
0
1
0
1
0
0
1
d.
A
B
A+B
0
0
0
0
1
0
1
0
0
0
0
1
105.
Which is the correct truth table for the Boolean expression A’ * B’?
a.
A
B
A+B
0
0
1
0
1
0
1
0
0
0
0
0
b.
A
B
A+B
0
0
0
0
1
1
1
0
1
0
0
1
c.
A
B
A+B
0
0
1
0
1
0
1
0
1
0
0
1
d.
A
B
A+B
0
0
0
0
1
0
1
0
0
0
0
1
106.
Which is the Boolean expression corresponding to the truth table shown in the
diagram?
A
B
OUT
0
0
0
0
1
1
1
0
0
0
0
0
a.
b.
c.
d.
A*B
A’+B
A’*B
A*B’
107.
Which is the Boolean expression corresponding to the truth table
A
B
OUT
0
0
1
0
1
1
1
0
0
0
0
1
a.
b.
c.
d.
108.
A*B
A’+B
A’*B
A*B’
a.
b.
c.
d.
A simplified version for the Boolean expression A+A’ is:
1
0
A’*A
A*A’
a.
b.
c.
d.
A simplified version for the Boolean expression A*A’ is:
1
0
A
A*A
a.
b.
c.
d.
A simplified version for the Boolean expression A+A*A is:
A*B
A’+B
A’*B
A
a.
b.
c.
d.
The simplified version for the Boolean expression A*B*B*A+A*A+B*B is:
A*B
A+B
A’*B
(A*B)’
109.
110.
111.
112.
A
B
The Boolean expression corresponding to this circuit is:
C
a.
b.
c.
d.
113.
A
B
AC+AB+BC
AC+AB+BA
ABC+A+B+BC
AC+AB+B’C
The Boolean expression corresponding to this circuit is:
C
a.
b.
c.
d.
ABC
A+B+C
(A+B+C)’
(ABC)’
114.
The Boolean expression corresponding to this circuit is
A
B
C
a.
b.
c.
d.
115.
A’+B’+C
A+(B+C)’
(A+B+C)’
(ABC)’
Which clock signal has the highest frequency?
A
B
C
a. A
b. B
c. C
116.
Clock input A and B are inputs to a gate. The output of the gate is signal C.
Which gate produces the waveform shown below.
a. AND gate
b. OR gate
c. NAND gate
d. NOR Gate
117.
a.
b.
c.
d.
A carry results when which of the following two numbers are added?
11
10
01
00
118.
a.
b.
c.
d.
If the binary Number 0111 and 1010 are added, the result will be
11000
10001
101010
11110
a.
b.
c.
d.
Which of the following is true of a half adder?
It can add two digits with a carry
It doesn’t have a carry out
It works on three bits at the same time
It can be connected to another half adder to add two bits to two other bits
a.
b.
c.
d.
The one’s complement of 0110 is
1001
1100
0011
Indeterminate
a.
b.
c.
d.
Which two gates are needed to make a half adder?
AND and OR
XOR and NAND
XOR and AND
Two NOR gates
a.
b.
c.
d.
The Boolean expression for a half adder is
A XOR B
A AND B
A OR B
Two NOR gates
a.
b.
c.
d.
The Boolean expression for the carry bit of a half adder is:
A XOR B
A AND B
A OR B
A AND B or G
119.
120.
121.
122.
123.
124.
a.
b.
c.
d.
The two’s compliment of 0110 is:
1001
1100
1010
Indeterminate
a.
b.
c.
d.
The half adder adds
Two inputs
Three inputs
Two inputs and a carry
4 inputs
125.
126.
a.
b.
c.
d.
A full adder
Has three inputs
Consists of two half adders
Can add two inputs and a carry
All of the above
Which of the following circuits is a half adder?
127.
SUM
CARRY
a.
SUM
CARRY
b.
SUM
CARRY
c.
SUM
CARRY
d.
128.
a.
b.
c.
d.
The difference between a serial adder and a parallel adder is:
Parallel adders add one bit at a time
Serial adders are faster
Parallel adders add all bit at the same time
Parallel adders do not use half adder circuits
a.
b.
c.
d.
The “∑” symbol represents
Sum
Product
Dividend
Equal
129.
130.
Which is the following symbol for a half adder?
a.
b.
c.
d.
131.
Which of the following is a full adder
a.
b.
c.
d.
132.
a.
b.
c.
d.
The circuit below is a:
3 bit adder
Full adder
Digital adder
Four bit adder
IC1
133.
a.
b.
c.
d.
In the circuit below, what data is present at point W?
Bit 1 sum
Bit 2 sum
The MSB
The carry bit
a.
b.
c.
d.
In the circuit for the question above, what data is present at point X?
Bit 1 sum
Bit 2 sum
The MSB
The carry bit
134.
135.
a.
b.
c.
d.
In the circuit for the question 132 above, what data is present at point Z?
Bit 1 sum
Bit 2 sum
The MSB
The carry bit
a.
b.
c.
d.
What logic function is performed by IC1?
Full adder
Half adder
Carry bit processor
MSB generator
a.
b.
c.
d.
Add the following binary numbers:
101 + 010 =
001 + 101 =
111 + 11 =
011 + 101 =
a.
b.
c.
d.
Subtract the following binary numbers using the two’s compliment method:
1100 – 0010 =
1101 – 1110
1110 – 0011 =
1111 – 0110 =
136.
137.
138.
139.
SUM
A
B
CARRY OUT
Draw the Logic symbol for a half adder, label all inputs and outputs
140.
Draw the logic symbol for a full adder, label all the inputs and outputs
141.
The basic building block for sequential logic is the
Flip-flop
Multiplexer
Sequential
Timer
a.
b.
c.
d.
142.
When a D flip-flop is used temporarily to store a bit of data and hold it until
needed, is commonly call a
a. Counter
b. Timer
c. Delay
d. Latch
143.
The normal output Q of a flip-flop is a logical____ when the nit is at rest.
a. O
b. 1
c. None of the above
144.
a.
b.
c.
d.
The particular type of flip-flop is considered the universal flip-flop
RS flip-flop
D flip-flop
JK flip-flop
None of the above
a.
b.
c.
d.
This particular type of flip-flop has only one input besides the clock input.
RS flip-flop
D flip-flop
JK flip-flop
None of the above
145.
146.
A positive-edge-triggered flip-flop changes state on the _____ transition of the
clock pulse.
a. Zero to one
b. One to zero
c. All of the above
d. None of the above
147.
A negative-edge-triggered flip-flop changes state on the _____ transition of the
clock pulse.
a. Zero to one
b. One to zero
c. All of the above
d. None of the above
148.
a.
b.
c.
d.
Two crossed NAND gates can form this type of flip-flop
RS flip-flop
D flip-flop
JK flip-flop
None of the above
a.
b.
c.
d.
A 555 timer can be used as the following types of clocks:
Monostable multivibrator (one shot)
Free-running multivibrator (astable)
Both A and B
All of the above
149.
150.
When the outputs of the RS flip-flop change only on a clock pulse we say that the
flip-flop operates in step with the clock. Another term for this is:
a. Synchronously
b. Asynchronously
c. Latched
d. Unilaterally
151.
pulse
a.
b.
c.
d.
A flip-flop is said to ________ when the Q outputs change states on each clock
Feedback
Latch
Toggle
Set
152.
A circuit that belongs to the flip-flop family but which has only one stable state
(normally Q=0)
a. One shot
b. Monostable multivibrator
c. Both A and B
d. None of the above
153.
A digital circuit accepts binary data from some input sourceand then shifts this
data through a series of flip-flops one at a time.
a. Flip-flop
b. Latch
c. Multivibrator
d. Shift register
154.
a.
b.
c.
d.
Another name for a flip flop
Bistable multivibrator
BCD adder
Decoder
Data line
a.
b.
c.
d.
To operate a JK flip-flop as a clocked RS flip-flop you
Add the inverter between the K and K inputs
Cross-couple the outputs ( Q and Q’) to the K and K inputs
Operate as is but avoid the J and K inputs both being high
None of the above
a.
b.
c.
d.
To operate a JK flip-flop as a D flip-flop you
Add an inverter between the J and K inouts
Operate as is but avoid the J and K inputs both being high
Make the J and K inputs both high and pulse the clock output
None of the above
155.
156.
157.
When the output of the flip-flop changes anytime the input changes the
condition is said to be
a. Asynchronously
b. Synchronously
c. Positive transition of the clock
d. Negative transition of the clock
158.
a.
b.
c.
d.
The action of clearing a flip-flop can also be referred to as
Clocking
Output
Setting
Resetting
a.
b.
c.
d.
e.
Flip-flops can be applied in the following applications
Ripple counters
Ring counters
Debounce circuits
Memory devices
All of the above
159.
160.
When JK flip-flops are wired as a ripple counter the pulses are tallied, and the
total appears in ________ form at the outputs of the circuit
a. Decimal
b. Binary
c. Hexadecimal
d. Octal
161.
a.
b.
c.
d.
A decoder is used with an alphanumeric readout to
Convert binary inputs to hexadecimal readout
Increase the current flow to each segment
Reduce current flow to the segments
Convert hexadecimal inputs to binary outputs
a.
b.
c.
d.
The Ripple clock and maximum/minimum outputs on a BCD counter
Are used to increase the count length by cascading the counters
Produce a pulse whenever an overflow or underflow occurs
Have opposite trigger levels when an overflow or underflow occurs
All of the above
a.
b.
c.
d.
In a synchronous counter
All of the flip-flops are toggled at the same time by the same clock pulse
The data changes bit by bit
Each flip-flop receives its clock pulse from the previous flip-flop
Each flip-flop is toggled by separate clock signals
162.
163.
164.
a.
b.
c.
d.
A ripple counter is
Asynchronous counter
Parallel counter
BCD counter
Synchronous counter
a.
b.
c.
d.
A binary counter having a maximum count of 63 requires how many flip-flops
4
5
6
7
a.
b.
c.
d.
The maximum count of a mod 16 counter is
One less than the modulus (15)
One more than the modulus (17)
The same as the modulus (16)
2N-1
a.
b.
c.
d.
e.
The decade counter has____ states
16
2
8
5
6
165.
166.
167.
168.
When using the decode and clear method to construct a mod 8 counter how
many inputs are needed on the control gate?
a. 1
b. 2
c. 3
d. 4
169.
a.
b.
c.
d.
The circuit shown below is a(n)
Ripple counter
Serial counter
Synchronous up counter
Asynchronous down counter