Name: ________________________ Class: ___________________ Date: __________
ID: A
Digital Electronics Final Review
True/False
Indicate whether the statement is true or false.
____
1. The current entering a node must equal the current leaving the node.
____
2. A digital audio system makes a copy of the waveform.
____
3. The binary number system is a positional notation system.
____
4. The number of cells in a K-map (Karnaugh map) is always a power of 2, usually 4, 8, or 16.
____
5. When grouping terms for simplification, every pair of terms must have at least one term that belongs only to
that pair.
____
6. A demultiplexer performs the reverse function of a multiplexer.
____
7. Latches and flip-flops are used as integral parts of more complex devices.
____
8. The simplest memory device is the D flip-flop.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
9. _____ states that the voltage across a component is equal to the resistance of the component multiplied by the
current through the component.
a.
b.
Kirchhoff’s Voltage Law
The SI System
c.
d.
Ohm’s Law
Kirchhoff’s Current Law
____ 10. A _____ is a junction of electronic components.
a.
b.
parallel
series
c.
d.
circuit
node
____ 11. Seven thousand volts can be expressed as
a. 7 MV
b. 7 kV
c.
d.
7000 V
b and c
____ 12. Express 7.32 × 10 7 in engineering notation
a. 732 × 10 7
b. 73.2 × 10 6
c.
d.
.732 × 10 6
732 × 10 6
1
Name: ________________________
ID: A
____ 13. At currents as low as _______, death is possible.
a.
b.
15 mA
5 mA
c.
d.
25 mA
50 mA
____ 14. The most common component in electronics is/are _____.
a.
b.
a solder joint
resistors
c.
d.
capacitors
alloys
____ 15. ______ usually look like a can with legs (leads) coming from the bottom.
a.
b.
Most resistors
Ceramic capacitors
c.
d.
Tantalum capacitors
Electrolytic capacitors
____ 16. Lightning is the discharge of _____ between the atmosphere and the ground.
a.
b.
current
voltage
c.
d.
static electricity
electrocution
____ 17. Resistors are _____; in other words, they can go into a circuit in either direction.
a.
b.
not polarized
axial-leaded
c.
d.
polarized
tin-tipped
____ 18. _____ are typically found as axial-lead packages.
a.
b.
Ceramic capacitors
Electrolytic capacitors
c.
d.
Tantalum capacitors
Resistors
____ 19. A proton is:
a.
b.
c.
d.
the center of an atom
the fundamental building block of molecues
a positively charged particle found in the nucleus of the atom
a negativley charged particle orbiting the nucleus of an atom
____ 20. A circuit built functionally the same as a circuit that is to be tested is a _____.
a.
b.
simulation
schematic
c.
d.
programmable device
prototype
____ 21. The atomic number of an element is the number of _____ in the nucleus of an atom of that element.
a.
b.
molecules
noble elements
c.
d.
2
protons
electrons
Name: ________________________
ID: A
____ 22. A _____ is a copper line on a circuit board connecting one component to another; it is a path for current to
flow on a circuit board.
a.
b.
conductor
trace
c.
d.
breadboard
node
c.
d.
rising and falling edge
most significant bit
____ 23. The rightmost bit of a binary number is the:
a.
b.
rising edge
least significant bit
____ 24. For the binary numbers from 0000 to 1111, the decimal equivalents are _____.
a.
b.
0 to 10
0 to 15
c.
d.
1 to 15
1 to 10
____ 25. An _______ is shown by a bubble or an arrow symbol on the affected terminal.
a.
b.
active HIGH
inversion
c.
d.
active LOW
opposite logic level
____ 26. A _______ directs a single input signal to one of several outputs.
a.
b.
demultiplexer
CMOS analog switch
c.
d.
multiplexer
priority encoder
____ 27. In the expression x + y = z, x and y are the ______.
a.
b.
augends
operands
c.
d.
addends
sum bits
____ 28. In the following multiplication problem what is the multiplier?
15
x 43
645
a.
b.
15
43
c.
d.
both 15 and 43
645
____ 29. ______ such as adders, multiplexers, and decoders are useful on their own and in combination as part of
more complex circuitry.
a.
b.
Enable signals
System level components
c.
d.
3
Control lines
Combinational logic functions
Name: ________________________
ID: A
____ 30. The difference between a latch and a flip-flop is:
a.
b.
c.
d.
they are activated by opposite logic levels
the present combination of inputs
the condition under which the stored bit is allowed to change
the fixed intervals during which changes occur
____ 31. ______ is the part of a signal where the logic level is in transition from a LOW to a HIGH
a.
b.
Rising edge
Leading edge
c.
d.
Trailing edge
Falling edge
c.
d.
State machines
Shift registers
c.
d.
four state variables
no state variables
____ 32. ______ are circuits that store and move data.
a.
b.
Counters
Ring counters
____ 33. A state machine that has two states requires:
a.
b.
only one state variable
two state variables
Completion
Complete each statement.
34. Complete a truth table for the following logic circuit and write the logic expression.:
35. Complete a truth table for the following logic circuit and write the logic expression.:
4
Name: ________________________
ID: A
36. Draw the logic circuit for the following expression (A+B)C = D
37. Hertz is the unit of ___________
38. The unit of resistance is ____________
39. The unit of voltage is _________
40. The unit of current is ______________
41. The unit of capacitance is ______________
42. The unit of power is ____________
43. Express 2000000 in scientific notation
44. Express 0.002 in scientific notation
45. Express 2.5 × 10 −6 as a decimal
46. Express 5 × 10 2 as a decimal
47. Express 4500000 in S.I. for a resister
48. Express .000008 in S.I. for current
49. Convert 7 mA to µA
Short Answer
50. What effect does a conductor have on electrical current?
51. What effect does an insulator have on electrical current?
5
Name: ________________________
ID: A
52. Use the chart to find the following resister size.
(Brown/Black/Brown/Gold) ______________
6
Name: ________________________
ID: A
Problem
53. Find I T ,V R1 ,V R2 ,R T for the given circuit.
54. Find I T ,I R1 ,I R2 ,R T for the given circuit.
7
Name: ________________________
ID: A
55. Find I T ,I R1 ,I R2 ,R T ,V R3 ,V R2 ,V R1 for the given circuit.
56. Convert the decimal number 23 to binary
57. Convert the decimal number 30 to binary
58. Convert the binary number 1010 to decimal
59. Convert the binary number 111000 to decimal
60. Simplify using Boolean Algebra
A(A + AB) =
61. Simplify using Boolean Algebra
XY+ XY =
62. Simplify using Boolean Algebra
ZW + ZW + XZW =
63. Simplify using De Morgans Theorems
X +Y
64. Simplify using De Morgans Theorems
A
8
Name: ________________________
ID: A
65. Simplify using De Morgans Theorems
PQR + P QR
66. Write the minterms for the following truth table:
A
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
B
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
C
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
D
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Output
0
1
0
0
0
0
1
0
0
0
0
0
1
0
0
0
Other
67. Know the following:
Basic structure of an atom
Ohms law
What a breadboard is used for
What a node is
Units for current, voltage and resistance
Kirchoff’s Current law
Kirchoff’s Voltage law
What an insulator is
What a conductor is
How to solve a basic series circuit, basic parallel circuit and a basic series combine with a parallel circuit.
9
ID: A
Digital Electronics Final Review
Answer Section
TRUE/FALSE
1.
2.
3.
4.
5.
6.
7.
8.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
T
F
T
T
T
T
T
T
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
MULTIPLE CHOICE
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
C
D
D
B
D
B
D
C
A
D
C
D
C
B
B
B
C
A
B
B
D
C
A
D
A
1
ID: A
COMPLETION
34. ANS:
ABCD E
0000 0
0001 0
0010 0
0011 0
0100 0
0101 1
0110 1
0111 1
1000 0
1001 1
1010 1
1011 1
1100 0
1101 1
1110 1
1111 1
PTS: 1
35. ANS:
ABC D
000 0
001 0
010 0
011 1
100 0
101 1
110 0
111 1
(A+B)(C+D)=E
(A+B)C=D
PTS: 1
36. ANS:
PTS: 1
37. ANS: Frequency
PTS: 1
2
ID: A
38. ANS: Ohm
PTS: 1
39. ANS: Volt
PTS: 1
40. ANS: Ampere
PTS: 1
41. ANS: Farad
PTS: 1
42. ANS: Watt
PTS: 1
43. ANS: 2 × 10 6
PTS: 1
44. ANS: 2 × 10 −3
PTS: 1
45. ANS: .0000025
PTS: 1
46. ANS: 500
PTS: 1
47. ANS: 4.5MΩ
PTS: 1
48. ANS: 8µA
PTS: 1
49. ANS: 7000µA
PTS: 1
SHORT ANSWER
50. ANS:
A conductor is a material that allows electrical current to flow through it easily, with a very low resistance.
PTS: 1
51. ANS:
An insulator is a material that does not allow electrical current to pass through, with a very high resistance.
PTS: 1
3
ID: A
52. ANS:
100Ω ± 5%
PTS: 1
PROBLEM
53. ANS:
I T = 6mA
V R1 = 4.8V
V R2 = 7.2V
R T = 2kΩ
PTS: 1
54. ANS:
I T = 24mA
I R1 = 16mA
I R2 = 8mA
V R1 = 12V
V R2 = 12V
R T = 500Ω
PTS: 1
55. ANS:
Reduce to a series circuit to find R T , then use R T and V to find I T
Find vdrop across R 3 . Subtract V R3 from 12 volts to get V R1 and V R2 use
V R1 and V R2 to calculate I R2 and I R1
I T = 11.6mA
I R1 = 8.2mA
I R2 = 3.42mA
V R3 = 5.82V
V R1 = V R2 = 6.17V
R T = 1029.4Ω
PTS: 1
56. ANS:
10111
PTS: 1
57. ANS:
11110
PTS: 1
4
ID: A
58. ANS:
10
PTS: 1
59. ANS:
56
PTS: 1
60. ANS:
0
PTS: 1
61. ANS:
X
PTS: 1
62. ANS:
W
PTS: 1
63. ANS:
XY
PTS: 1
64. ANS:
A
PTS: 1
65. ANS:
0
PTS: 1
66. ANS:
ABCD + ABCD + ABCD
PTS: 1
OTHER
67. ANS:
See your notes or google
PTS: 1
5