The op amp circuit has been connected for a long time.
Determine the power absorbed by the 2-k resistor.
Fall 2014, Quiz #2
Answer: 18 mW
1
Parts (a)–(c) refer to this circuit, which has been connected for a long time.
Determine the amount of electromagnetic energy stored in
(a) the 6-H inductor, (b) the 3-F capacitor, and (c) the 7-mH inductor.
Fall 2013, Exam #3, Problem #1
Answers: (a) 48 J , (b) 96 J , (c) 0 J
2
For parts (a) and (b), assume the inductance of the passive element is L = 4 mH.
(a) Given vL(t) in the plot, sketch iL(t) . Assume iL(–1) = 0.
(b) Given iL(t) in the plot, sketch vL(t) .
Fall 2013, Exam #3 sample A, Problem #3
Answers: (a) trapezoid with h = 3 mA , (b) –28sin(t) V
3
Given v(t) and i(t) for a passive element as plotted below, determine its capacitance C .
Fall 2013, Exam #3 sample A, Problem #4
Answer: 5 F
4
For parts (a) and (b), assume the capacitance of the passive element is C = 8 F .
(a) Given iC(t) in the plot, sketch vC(t) . Assume vC(–1) = 0.
(b) Given vC(t) in the plot, sketch iC(t) .
Fall 2013, Exam #3 sample B, Problem #3
Answers: (a) ramp from 0 V up to 5 V from t = 0 to t = 2 , (b) 40cos(t) A
5
Given v(t) and i(t) for a passive element as plotted below, determine its inductance L .
Fall 2013, Exam #3 sample B, Problem #4
Answer: 6 mH
6
For parts (a) and (b), assume the inductance of the passive element is L = 5 mH.
(a) Given iL(t) in the plot, sketch vL(t) .
(b) Given vL(t) in the plot, sketch iL(t) . Assume iL(–1) = 0.
Fall 2013, Exam #3 sample C, Problem #1
Answers: (a) 150 – 75u(t – 1 ms) – 175(t – 3 ms) mV , (b) 2 ramps, up to 20 mA & 40 mA
7
The source voltage is vs  t   5  9u  t  V . Determine the sum total of the energy stored in the
capacitors after the circuit has settled, a long time after t = 0 .
Fall 2014, Exam #3, Problem #3
Answer: 24 J
8
Given v(t) and i(t) for the inductor circuit below, determine the value of the inductance, L .
Fall 2014, Exam #3, Problem #4
Answer: 8 mH
9
Parts (a)–(c) refer to the plot of capacitor current below.
Assume that the voltage across the capacitor vC = 0 at t = 0 .
For a capacitance of C = 4 F , determine vC at (a) t = 1.0 ms, (b) t = 3.0 ms, and (c) t = 7.2 ms.
Fall 2013, Take-home exam, Problem #2(a)-(c)
Answers: (a) 3 V , (b) 23 V , (c) 28 V
10
Parts (a)–(c) refer to the plot of current below for an inductor with L = 3 mH .
Determine the voltage across the inductor vL at (a) t = 1.7 ms , (b) t = 3.2 ms , and (c) t = 4.4 ms.
Fall 2013, Take-home exam, Problem #2(e)-(f)
Answers: (a) 27 mV , (b) –72 mV , (c) 0 mV
11
The circuit below has been connected for a long time.
Determine the electromagnetic energy stored in the 4-F capacitor.
Fall 2013, Final exam, Problem #2
Answer: 162 J
12
Determine the amount of energy stored in the inductor, a long time after t = 0 .
Fall 2014, Final exam, Problem #9(b)
Answer: 40 nJ
13
The DC circuit below has been connected for a long time. Determine v1, v2, v3, v4, i1, i2, i3, the
power absorbed by each resistor, and the electromagnetic energy stored in the 3-mH inductor and
the 5-F capacitor.
Fall 2014, Final exam review, Problem #1
Answers: v1 = 12 V , v2 = 12 V , v3 = –4 V , v4 = 8 V , i1 = 6 mA ,
i2 = –4 mA , i3 = 2 mA , wL = 54 nJ , wC = 40 J
14
The DC circuit below has been connected for a long time. Determine (a) v, (b) vs , (c) i , (d) the
power absorbed by each resistor, and (e) the electromagnetic energy stored in each capacitor.
Fall 2014, Final exam review, Problem #11
Answers: (a) –4 V , (b) 4 V , (c) –1/2 A , (d) 2 W , 4 W , (e) 32 J , 24 J , 64 J
15
Reduce the circuit below to as few components as possible, and then determine v and i ,
assuming that the circuit has been connected for a long time.
Fall 2014, Final exam review, Problem #13(b)
Answers: v = 0 V , i = 4 A
16
The current flowing through a 33-mF capacitor is shown graphically below. (a) Assuming the
passive sign convention, sketch the resulting voltage across the device. (b) Compute the voltage
at 300 ms, 600 ms, and 1.1 s .
Fall 2013, Homework #7, Problem #1
Answers: (b) 48.5 V , 72.7 V , 121.2 V
17
Calculate the voltage labeled vx in the circuit below, assuming the circuit has been running a very
long time, if (a) a 10- resistor is connected between terminals x and y , (b) a 1-H inductor is
connected between terminals x and y , (c) a 1-F capacitor is connected between terminals x and
y , and (d) a 4-H inductor in parallel with a 1- resistor is connected between terminals x and y .
Fall 2013, Homework #7, Problem #6
Answers: (a) 18.64 V , (b) 16.38 V , (c) 25.79 V , (d) 16.38 V
18
Reduce the network below to the smallest possible number of components if each inductor is
1 nH and each capacitor is 1 mF .
Fall 2013, Homework #7, Problem #3
Answer: 1.5 mF, in series with 0.5 nH || 3 mF, in series with 0.5 nH
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(a) Compute iL and vx as indicated in the circuit below.
(b) Determine the energy stored in the inductor and in the capacitor.
Fall 2013, Homework #7, Problem #7
Answers: (a) iL = –1.4 mA , vx = –630 mV , (b) wL = 2 pJ , wC = 200 nJ
20
Referring to the circuit below, calculate the energy stored in each energy storage element.
Fall 2013, Homework #7, Problem #4
Answers: wC = 8 J , wL = 4 mJ
21
Determine v(t) for t  0 for the circuit below when v(0) = –4 V and is(t) is the current shown
in the plot below.
Fall 2014, Homework #6, Problem #1
 4  40t 2

Answer: v  t    20t  6.5

3.5

0  t  0.25 s
0.25  t  0.5 s
t  0.5 s
22
The circuit shown below contains seven capacitors, each having capacitance C . The source
voltage is v(t) = 4cos(3t) V . Find the current i(t) when C = 1 F .
Fall 2014, Homework #6, Problem #2
Answer: –4.6sin(3t) A
23
The voltage v(t) and current i(t) of a 0.5-H inductor adhere to the passive convention. Also,
v(0) = 0 V , and i(0) = 0 A . (a) Determine v(t) when i(t) = x(t) , where x(t) is shown in the
plot below and i(t) has units of A . (b) Determine i(t) when v(t) = x(t) , where x(t) is shown
in the plot below and v(t) has units of V .
Fall 2014, Homework #6, Problem #3
0
t 2s
 0V 0t 2s



2
Answers: (a) v  t    0.1 V 2  t  6 s , (b) i  t    0.2t  0.8t  0.8 2  t  6 s
 0V

t 6s
1.6t  6.4
t 6s


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For the circuit below, (a) determine is(t) and (b) sketch is(t) for two cycles of the sinusoid.
Fall 2014, Take-home exam, Problem #7
Answers: (a) 12.6cos(2t) mA
25
In the circuit below, i(0) = 45 mA and the voltage v(t) is given in the plot.
Determine the value of the inductor current at t = 6 ms .
Fall 2015, Homework #6, Problem #1
Answer: 285 mA
26
The circuit below has been connected for a long time. Determine the current labeled ix .
Fall 2015, Homework #6, Problem #2
Answer: 2.86 A
27
For the circuit below, determine the equivalent capacitance Ceq .
Fall 2015, Homework #6, Problem #3
Answer: 3.6 F
28
The voltage and current for a capacitor
follow the passive sign convention, as illustrated.
The voltage v is plotted in the figure.
Assume that all line segments drawn in
the figure are perfectly straight.
Determine the power absorbed
by the capacitor at t = 9 s .
Fall 2015, Exam #3, Problem #1
Answer: –540 mW
29
The circuit below has been connected for a long time.
Determine the energy stored in the capacitor.
Fall 2015, Exam #3, Problem #3
Answer: 180 J
30
Determine the equivalent capacitance across terminals A–B .
Fall 2015, Final exam, Problem #1(b)
Answer: 14 pF
31
In the circuit below, determine the total energy stored in the capacitors,
a long time after the switch is closed.
Fall 2015, Take-home exam, Problem #6
Answer: 478 J
32