Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
The form of an exponential buildup expression is
1)
A)
A(1–e–t/)
B)
Ae–t/
C)
Ae+t/
D)
None of the above
2)
For aseries RC circuit, the time constant equals
2)
A)
C/R
B)
R/C
C)
1/(Rc)
D)
None of the above
3)
An exponential signal that starts at some finite non–zero value at t = 0and decreases toward zero as
time increases is called
3)
A)
an exponential buildup.
B)
an exponential growth.
C)
an exponential decay.
D)
None of the above
4)
At t5during buildup, the voltage across the resistor in aseries RL circuit is
4)
A)
equal to the source voltage.
B)
equal to the resistor voltage at t = 0.
C)
zero.
D)
Both Band C
5)
During buildup in aseries RC circuit
5)
A)
the sum of the voltage across the resistor and the voltage across the capacitor equals the source
voltage.
B)
the voltage across the resistor equals the voltage across the capacitor.
C)
the voltage across the resistor equals the source voltage at all times.
D)
the voltage across the capacitor equals the source voltage at all times.
6)
At t5,the voltage across the capacitor in acharging series RC circuit is
6)
A)
equal to the capacitor voltage at t = 0.
B)
equal to the source voltage.
C)
zero.
D)
None of the above
7)
The direction of the current through an inductor in aseries RL circuit during decay is
7)
A)
the same as the direction during buildup.
B)
the opposite of the direction during buildup.
C)
meaningless; there is no current through an inductor during decay.
D)
None of the above
8)
At t = 0, when aDC source is first switched on in aseries RC circuit (the capacitor is initially
uncharged), the current is
8)
A)
equal to the source voltage.
B)
zero.
C)
equal to the DC steady–state value.
D)
None of the above
9)
The form of an exponential decay expression is
9)
A)
A(1–e–t/)
B)
Ae–t/
C)
Ae+t/
D)
None of the above
10)
The polarity of the voltage across acapacitor in aseries RC circuit during decay is
10)
A)
the opposite of the polarity during buildup.
B)
the same as the polarity during buildup.
C)
meaningless; there is no voltage across acapacitor during decay.
D)
None of the above
11)
At t = 0, when aDC source is first switched on in aseries RL circuit (the current is zero before
switching), the voltage across the resistor is
11)
A)
equal to the source voltage.
B)
zero.
C)
equal to the DC steady–state value.
D)
None of the above
12)
At t = 0, when aDC source is first switched on in aseries RC circuit (the capacitor is initially
uncharged), the voltage across the resistor is
12)
A)
zero.
B)
equal to the DC steady–state value.
C)
equal to the source voltage.
D)
None of the above
13)
An exponential signal that starts at value 0at t = 0and builds toward infinity as time increases is
called:
13)
A)
an exponential buildup.
B)
an exponential decay.
C)
an exponential growth.
D)
None of the above
14)
An exponential signal that starts at value 0at t = 0and builds toward afinite value as time
increases is called
14)
A)
an exponential decay.
B)
an exponential buildup.
C)
an exponential growth.
D)
None of the above
15)
At t
5,the voltage across the resistor in acharging series RC circuit is
15)
A)
zero.
B)
equal to the resistor voltage at t = 0.
C)
equal to the source voltage.
D)
Both Band C
16)
At t = 0, when aDC source is first switched on in aseries RL circuit (the current is zero before
switching), the voltage across the inductor is
16)
A)
equal to the source voltage.
B)
equal to the DC steady–state value.
C)
zero.
D)
None of the above
17)
At t
5,the current in acharging series RC circuit is
17)
A)
equal to the current at t = 0.
B)
zero.
C)
equal to the source voltage divided by the resistance.
D)
None of the above
18)
At t = 0, when aDC source is first switched on in aseries RC circuit (the capacitor is initially
uncharged), the voltage across the capacitor is
18)
A)
equal to the source voltage.
B)
zero.
C)
equal to the DC steady–state value.
D)
None of the above
19)
The form of an exponential growth expression is
19)
A)
Ae–t/
B)
A(1–e–t/)
C)
Ae+t/
D)
None of the above
20)
At t5during buildup, the current in aseries RL circuit is
20)
A)
equal to the current at t = 0.
B)
equal to its DC steady–state value.
C)
zero.
D)
None of the above
21)
The polarity of the voltage across an inductor in aseries RL circuit during decay is
21)
A)
meaningless; there is no voltage across an inductor during decay.
B)
the opposite of the polarity during buildup.
C)
the same as the polarity during buildup.
D)
None of the above
22)
At t5during buildup, the voltage across the inductor in aseries RL circuit is
22)
A)
equal to the inductor voltage at t = 0.
B)
zero.
C)
equal to the source voltage.
D)
Both Band C
23)
The direction of the current through acapacitor in aseries RC circuit during decay is
23)
A)
meaningless; there is no current through acapacitor during decay.
B)
the opposite of the direction during buildup.
C)
the same as the direction during buildup.
D)
None of the above
24)
For aseries RL circuit, the time constant equals
24)
A)
L/R
B)
R/L
C)
1/(RL)
D)
None of the above
25)
At t = 0, when aDC source is first switched on in aseries RL circuit (the current is zero before
switching), the current is:
25)
A)
equal to the DC steady–state value.
B)
equal to the source voltage divided by the resistance.
C)
zero.
D)
None of the above
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
26)
A15 Vsource is switched on in aseries RL circuit (the current is initially zero). The resistor
is 12 ohmsand the inductor is 10 mH. The expression for the voltage across the inductor is
________.
26)
27)
A15 Vsource is switched on in aseries RL circuit (the current is initially zero). The resistor
is 12 ohmsand the inductor is 10 mH. Verify KVL: ________
27)
28)
Acharged capacitor is switched on in aseries resistor (the capacitor is initially charged to
15 V). The resistor is 5000 ohms and the capacitor is 10µF.The expression for the voltage
across the resistor is ________.
28)
29)
A15 Vsource is switched on in aseries RL circuit (the current is initially zero). The resistor
is 12 ohmsand the inductor is 10 mH. The expression for the current is ________.
29)
30)
Acharged capacitor is switched on in aseries resistor (the capacitor is initially charged to
15 V). The resistor is 5000 ohms and the capacitor is 10µF.The expression for the current
(assume the current direction is labeled in the direction that the current flowed during
charging) is ________.
30)
31)
A15 Vsource is switched on in aseries RL circuit (the current is initially zero. The resistor is
12 ohms and the inductor is 10 mH. The time constant is ________.
31)
32)
A15 Vsource is switched on in aseries RC circuit (the capacitor is initially uncharged). The
resistor is 330ohmsand the capacitor is 10 µF.The expression for the current is ________.
32)
33)
A15 Vsource is switched on in aseries RL circuit (the current is initially zero). The resistor
is 12 ohmsand the inductor is 10 mH. The expression for the voltage across the resistor is
________.
33)
34)
An inductor with 125mA of current flowing through it is switched to aseries resistor (a
make–before–break switch is used). The resistor is 5ohms and the inductor is 10 mH. The
expression for the current (assume the current direction is labeled in the direction that the
current flowed during charging): ________
34)
35)
A15 Vsource is switched on in aseries RC circuit (the capacitor is initially uncharged). The
resistor is 330ohmsand the capacitor is 10 µF.The time constant is ________.
35)
36)
An inductor with 125mA of current flowing through it is switched to aseries resistor (a
make–before–break switch is used). The resistor is 5ohms and the inductor is 10 mH. The
time constant is ________.
36)
37)
A15 Vsource is switched on in aseries RC circuit (the capacitor is initially uncharged). The
resistor is 330ohmsand the capacitor is 10 µF.Verify KVL: ________
37)
38)
A15 Vsource is switched on in aseries RC circuit (the capacitor is initially uncharged). The
resistor is 330ohmsand the capacitor is 10 µF.The expression for the voltage across the
resistor is ________.
38)
39)
Acharged capacitor is switched on in aseries resistor (the capacitor is initially charged to
15 V). The resistor is 5000 ohms and the capacitor is 10µF.The time constant is ________.
39)
40)
Acharged capacitor is switched on in aseries resistor (the capacitor is initially charged to
15 V). The resistor is 5000 ohms and the capacitor is 10µF.Verify KVL: ________
40)
41)
Acharged capacitor is switched on in aseries resistor (the capacitor is initially charged to
15 V). The resistor is 5000 ohms and the capacitor is 10µF.The expression for the voltage
across the capacitor is ________.
41)
42)
An inductor with 125mA of current flowing through it is switched to aseries resistor (a
make–before–break switch is used). The resistor is 5ohms and the inductor is 10 mH.
Verify KVL: ________
42)
43)
An inductor with 125mA of current flowing through it is switched to aseries resistor (a
make–before–break switch is used). The resistor is 5ohms and the inductor is 10 mH. The
expression for the voltage across the resistor is ________.
43)
44)
A15 Vsource is switched on in aseries RC circuit (the capacitor is initially uncharged). The
resistor is 330ohmsand the capacitor is 10 µF.The expression for the voltage across the
capacitor is ________.
44)
45)
An inductor with 125mA of current flowing through it is switched to aseries resistor (a
make–before–break switch is used). The resistor is 5ohms and the inductor is 10 mH. The
expression for the voltage across the inductor (assume the voltage polarity is labeled as the
polarity during buildup) is ________.
45)
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
46)
Current can never flow into and out of acapacitor because it is an open.
46)
47)
An exponential buildup approaches infinity as time increases.
47)
48)
An exponential decay approaches zero as time increases.
48)
49)
The only electronic signals that exist are DC steady–state and AC steady–state signals.
49)
50)
Voltage can never exist across an inductor because it is ashort.
50)
51)
The transient in either an RL or an RC circuit effectively lasts five time constants.
51)
52)
The ideal capacitor looks like an open to DC steady–state signals.
52)
53)
The time constant of aseries RC circuit is directly proportional to resistance.
53)
54)
The time constant of aseries RL circuit is directly proportional to resistance.
54)
55)
The time constant of aseries RC circuit is directly proportional to capacitance.
55)
56)
Amake–before–break switch is often used in inductive circuits to prevent an arc (spark) when the
circuit is turned off.
56)
57)
The time constant of aseries RL circuit is directly proportional to inductance.
57)
58)
The wire resistance of inductors can always be ignored in DC analysis.
58)
59)
The ideal inductor looks like an open to DC steady–state signals.
59)
60)
All voltage and current values in an RL circuit at the moment when aDC source is switched on are
equal to the DC steady–state values.
60)
Answer Key
Testname: C7
10
Answer Key
Testname: C7
11